The Implications of
Growing Short-Rotation Tree Species for
Carbon Sequestration in
Canada
Final Report
Prepared for
The Joint Forest Sector
Table/Sinks Table
Afforestation #5
National Climate Change
Process
Solicitation No:
23103-8-0253/N
Prepared by
R. Samson, P. Girouard,
C. Zan, B. Mehdi, R. Martin and J. Henning
April 1999
Resource Efficient
Agricultural Production (R.E.A.P.)-Canada
21,111 Lakeshore Road
Glenaladale House, P.O.
Box 125
Ste. Anne de Bellevue,
Québec
H9X 3V9
Telephone: (514)
398-7743; Fax: (514) 398-7972; E-mail: reap@interlink.net
Short rotation forestry (SRF) plantations have been
identified as a possible mitigation strategy for climate change. Short rotation
trees reduce greenhouse gas (GHG) emissions in two direct ways: by
afforestation, which has the potential to increase carbon storage in the
landscape compared to growing agricultural crops, and by sustainably-produced
plantations, which act as a closed-loop biofuel to substitute fossil fuels.
Indirectly, the end use of the SR tree plantations as a fibre source could also
reduce GHG emissions by relieving pressure on the intensity of natural forest
harvesting in Canada, thereby leaving the standing carbon levels in the natural
forests unscathed.
The most important SRF species that have been
identified to date are hybrid poplar (Populus sp.) and willow (Salix
sp.). Poplar is typically grown on a 10-15 year rotation at densities of
1,100-1,400 stems ha-1. The estimated yield ranges in Canada vary by
region, with the southern mainland of British Columbia having the highest
potential productivity (9-12 oven-dried megagrams per hectare (odMg ha-1yr-1)),
followed by Ontario and Québec (2.5-7 odMg ha-1yr-1), the
Atlantic provinces (2-6 odMg ha-1yr-1) and the Prairies
(1-5 odMg ha-1yr-1). Short-rotation willow is grown at
12,000-15,000 cuttings ha-1, is harvested on a 3-4 year cycle, and
can have a plantation life of 20-25 years. The southern mainland of British
Columbia has the highest potential productivity (10-15 odMg ha-1yr-1),
followed by Ontario and Québec (7-12 odMg ha-1yr-1), the
Atlantic provinces (5-10 odMg ha-1yr-1) and the Prairies
(2-6 odMg ha-1yr-1).
Few investigations of SRF root dynamics have been carried
out due to the tediousness of sampling procedures. Varying conditions such as
planting density, clone differences, nutrient inputs, age of rotations, timing
of coppice and differences in sampling methodologies have added to the variability
in the results reported. Root biomass is approximately equivalent to 20% of the
aboveground matter, however, SR tree species are found to have relatively lower
root production at higher soil nutrient levels. Carbon content of structural
and fine roots has been observed to be about 45% and 30-45%, respectively,
whereas the carbon concentration of SR tree stems has been found to be in the
range of 40-50%.
Few studies have been undertaken on the potential for soil
carbon sequestration under SRF systems. Soil carbon storage data have typically
been collected at single sampling dates rather than providing information on
long-term soil carbon dynamics. These methodological limitations have made it
difficult to assess the true impact of the various SRF systems on soil carbon
storage levels. Nonetheless, rotation length is a key factor in the ability of
plantations to remove carbon from the atmosphere over the long-term. The longer
the rotation length, the greater the soil carbon storage potential. Very short
rotations (less than 10 years) may therefore not lead to soil carbon
sequestration. In fact, carbon is most probably lost during the establishment
phase of the plantations. As well, under improper soil fertility management,
there may not be any advantages of growing SR plantations for soil carbon
storage.
In terms of establishing SR plantations, the technology to
grow SR trees has advanced rapidly in the last 15 years in temperate climatic
zones. No major production constraints exist for producing or harvesting hybrid
poplar or willow, although further improvements in cultural practices can be
made. Greater investment in plant breeding may improve productivity, reduce
risks of stand failure, and reduce disease and insect problems. One of the
constraints to increasing yields was the high water demand.
Extensive research has been performed on the environmental
impacts of SRF systems. When properly managed, SRF plantations have a positive
impact on the environment, compared to agricultural crops. Short rotation
forestry systems limit soil erosion, decrease pesticide impacts and fertilizer
applications, and increase biological diversity. However, negative impacts may
occur, especially during the establishment and harvest phases. As well,
increasing the management intensity of SR plantations by establishing
large-scale operations, increasing chemical and irrigation usage, and the use
of genetically engineered crops, may lead to a loss of these positive impacts.
Costs involved in growing SR willow and hybrid
poplar were estimated using BIOCOST-Canada and BIOCOST-USA
softwares. Estimates of the variable (vc) and full economic costs (fc) of
production for both crops were performed for all regions of Canada. In general,
regions with longest growing seasons and most favourable climates had the
lowest cost of production. The cost of producing willow was lower than poplar
due to higher productivity levels. The lowest cost of willow production was in
British Columbia (vc $50-64 odMg-1; fc $60-78 odMg-1),
where highest productivity were observed, followed by Ontario and Québec (vc
$57-82 odMg-1; fc $69-102 odMg-1), and the Atlantic
provinces (vc $64-92 odMg-1; fc $78-116 odMg-1). Highest
costs were in the Prairie provinces where productivity was lowest (vc $92-106
odMg-1; fc $115-134 odMg-1). Similarly, the lowest cost
for poplar production was in British Columbia (vc $62-73 odMg-1; fc
$80-97 odMg-1) followed by Ontario and Québec (vc $82-112 odMg-1;
fc $112-160 odMg-1), the Atlantic provinces (vc $91-115 odMg-1;
fc $127-164 odMg-1) and the Prairies (vc $104-120 odMg-1;
fc $146-173 odMg-1).
Potential industrial uses of SR tree species
include fibre markets and energy markets. Most commercial interest lies in the
production of single-stemmed poplars for fibre applications. There is little
commercial interest in coppiced willows as an energy crop with the current
market conditions. However, closed-loop biofuels have the potential to reduce
greenhouse gas emissions significantly.
As a renewable energy source, willow appears to
be uncompetitive in most current applications. Eastern Canada has the greatest
bioenergy opportunity, as fossil energy prices are generally higher than in
other regions of the country. Obstacles to the commercialization of SR willow
as an energy crop include low cost forest and agricultural crop residues, and
the lower cost of production of perennial grass biomass feedstocks. As well,
there is some farmer preference for agricultural crop residues and herbaceous
energy crops. Liquid fuel and electricity production from dedicated SR tree
plantations in large industrial plants are the least viable option for
bioenergy production. The direct heat applications of wood chip heating and
pelleting are the most promising economically viable options and warrant a
comprehensive analysis. A large number of small- and medium-sized wood chip
combustion systems could be installed for space and process heat applications
in many rural areas of Canada. As well, willows could be densified and burned
in gasifier pellet stoves and furnaces to replace oil, propane and electricity.
The decentralized production and utilization of bioenergy crops is well adapted
to rural energy applications, where fossil fuel energy costs are higher.
A strong commercial interest in the planting of
poplars in many regions of Canada exists, as many industry analysts are
concerned about the sustainability of fibre supply. Poplar can be used for a
variety of fibre products including pulp and paper, oriented strand board,
particle board, some solid wood products, and engineered lumber. Current
industry procurement costs are approximately $100 per tonne, which is
considerably higher than bioenergy market values. There is generally a lack of
production information on the cultivation of poplars on longer rotations for
the solid wood products industry. Poplars have a strong market potential in the
rapidly evolving engineered lumber industry.
Afforestation programs in the northern United
States and Canada are based almost exclusively on poplars for the production of
pulp and paper and oriented strand board. In the United States, rapidly
developing programs are underway. The Pacific Northwest region has 26,900 ha of
poplar in cultivation. The North-Central region has less acreage, but forecast
plantings suggest it will lead the United States in acreage in the next 5 years
due to the concerns about fibre supply in the region. In Canada, in Eastern
Ontario, approximately 2,400 ha of poplars have been planted on
privately-leased and land owned by Domtar Forest products. In British
Columbia, a total of 3,600 ha of poplars have been planted by McMillan
Bloedel and Scott paper company. There is an industry consortium
interested in the production of poplars (and aspen) in the region north of
Edmonton, Alberta. However, the long harvest rotations forecasted and the
unproven SR tree productivity in this northern region make it a high risk SR
tree growing area. The main reason for the plantations in the area is the
forecasted fibre shortages.
Three factors were identified to develop a
successful afforestation program: 1. A perceived need for fibre by industry, 2.
Requisite talent in the form of silviculturalists and tree breeders with
adapted materials and 3. A suitable land base. No region in Canada has all
three components in place at the present time, however, southern Québec has
been identified as a region with high potential. British Columbia has
attractive growth rates and costs but lacks a significant land base in the
southern mainland to create a significant industrial impact. Currently, eastern
Ontario has no strong demand requirements for hardwood fibre. Northern Alberta
has a strong industry demand, but limited experience with plant materials and a
northern land base with modest rainfall, which would suggest low potential
productivity. Southern Manitoba and Nova Scotia also hold good potential for
afforestation programs, but there is limited experience in these areas.
Class 4 and 5 agricultural land was identified
as the main land base for afforestation. An afforestation program using SR
hybrid poplar and willow, possibly in the order of 4.25 to 12.75 million ha
could be available. However other bioenergy and agri-fibre crops such as
perennial grasses would be competing for access to these lands for energy and
fibre markets and are better adapted to lower rainfall regions and soils with a
low water-holding capacity. A more detailed analysis is required to more
effectively analyze the land base availability for SR tree plantations.
One of the main issues to address when
developing policies to mitigate GHG emissions is the relative cost of each
policy option that is required to achieve the desired objective. All carbon
sequestration scenarios investigated in this study included a soil organic
carbon accumulation rate of either 1.5 or 3.0 Mg C ha-1 yr-1,
with some scenarios including an additional carbon sequestration from increases
in biomass carbon stocks compared with previous land-use. Carbon sequestration
values were computed both over the entire life span of the plantations (12 and
20 years for hybrid poplars and willows, respectively), and over the first
commitment period of the Kyoto period, 2008 to 2012. The cost of sequestering
carbon varied generally between $14-$54 Mg-1 of CO2 for
hybrid poplar and $4-$49 Mg-1 of CO2 in willow, for all
scenarios involving a soil organic carbon accumulation rate of 1.5 Mg C ha-1
yr-1. Doubling soil organic carbon accumulation rate (3.0 Mg ha-1yr-1)
reduces the amount of carbon sequestered by approximately half.
Overall, this study indicates that the least
risky strategy to rapidly implement afforestation programs, for carbon
sequestration in Canada, involves the production of SR hybrid poplars for fibre
applications. Commercial risk with poplars is reduced compared to SR willow
plantations, as SR poplars are already grown for fibre in North America and
competitive market prices for the chips is approximately twice that for energy
applications. This can be achieved, while at the same time incurring costs of
carbon sequestration similar to those of willows. The main limitation of the
study is that the carbon offset occurring over the complete life-cycle of the
biomass produced from hybrid poplars and willow is not estimated.
Executive
Summary................................................................................................................. ii
List
of Tables
.......................................................................................................................
ix
List
of Figures
.......................................................................................................................
x
List
of
Appendices...................................................................................................................
xi
List
of Symbols xii
Introduction
.......................................................................................................................
1
Task
1 Estimates of Short-Rotation-Forestry Growth and Carbon Sequestration
Potential
.......................................................................................................................
3
1.1.
Aboveground Biomass..................................................................................................... 3
1.1.1. Productivity..................................................................................................... 3
1.1.1.1. Introduction........................................................................................ 3
1.1.1.2. Major Findings................................................................................... 3
1.1.2.
Carbon............................................................................................................. 8
1.2.
Root Biomass.................................................................................................................. 8
1.2.1.
Productivity...................................................................................................... 8
1.2.1.1.
Introduction........................................................................................
8
1.2.1.2.
Limitations..........................................................................................
9
1.2.1.3.
Major
Findings...................................................................................
9
1.2.2.
Carbon............................................................................................................. 10
1.2.3.
Conclusions...................................................................................................... 11
1.3.
Soil Carbon Sequestration............................................................................................... 14
1.3.1.
Introduction....................................................................................................... 14
1.3.1.1.
Hypothesis.........................................................................................
14
1.3.1.2.
Limitations..........................................................................................
14
1.3.2.
Major Findings.................................................................................................. 15
1.3.3.
Conclusions....................................................................................................... 18
1.3.4.
Suggestions for Future Research........................................................................ 18
Literature
Cited
19
Task
2 Issues Related to Short-Rotation Forestry Culture............................................... 24
2.1.
Introduction.....................................................................................................................
24
2.2.
Production Practices of SRF............................................................................................ 24
2.2.1.
Willow.............................................................................................................. 24
2.2.1.1.
Production..........................................................................................
24
2.2.1.2.
Harvest..............................................................................................
25
2.2.1.3.
Breeding
Programs.............................................................................
25
2.2.2.
Poplar............................................................................................................... 25
2.2.2.1.
Production..........................................................................................
25
2.2.2.2.
Harvest..............................................................................................
26
2.2.2.3
Breeding
Programs.............................................................................
26
2.2.3.
Conclusions....................................................................................................... 27
2.3.
Environmental Impacts Associated with Growing SRF Systems........................................ 27
2.3.1.
Insect and Disease Damage............................................................................... 27
2.3.2.
Pesticide Loading.............................................................................................. 28
2.3.3.
Water Use......................................................................................................... 29
2.3.4.
Soil Erosion....................................................................................................... 30
2.3.5.
Nutrient Losses................................................................................................. 31
2.3.6.
Biodiversity....................................................................................................... 32
2.3.7.
Conclusions....................................................................................................... 33
Literature
Cited
34
Task
3. Costs of Production................................................................................................. 37
3.1.
Introduction.....................................................................................................................
37
3.2.
Assumptions....................................................................................................................
37
3.3.
Production Cost Estimates............................................................................................... 38
Literature
Cited
40
Task
4. Industrial Use and Market Returns....................................................................... 41
4.1.
Introduction.....................................................................................................................
41
4.2. Electricity Generation....................................................................................................... 41
4.3. Space and Process Heat
Applications.............................................................................. 43
4.4.
Pellet
Fuel
45
4.5.
Cellulosic
Ethanol............................................................................................................
46
4.6.
Pulp and Paper Production.............................................................................................. 48
4.7.
Solid Wood and Related Products................................................................................... 49
4.7.1.
Particle Board and Medium Density Fibre Board and Oriented
Strand
Board...................................................................................................
49
4.7.2
Solid Wood Products........................................................................................ 49
4.7.3
Engineered Lumber............................................................................................ 50
Literature
Cited
50
Task
5. Economics of Carbon Sequestration..................................................................... 52
5.1.
Introduction.....................................................................................................................
52
5.2.
Estimated Carbon Accumulation...................................................................................... 52
5.2.1.
Carbon in Aboveground Standing Tree Biomass................................................. 52
5.2.2.
Carbon in Belowground Biomass....................................................................... 54
5.2.3.
Soil Organic Carbon Pool.................................................................................. 55
5.3.
Cost Estimates of Carbon Sequestration........................................................................... 55
5.3.1.
Cost of sequestering soil organic carbon............................................................. 56
5.3.1.1. Scenario 1: Entire
plantations lifespan................................................. 56
5.3.1.2. Scenario 2: Commitment
period 2008-1012 only............................... 57
5.3.2.
Cost of sequestering carbon in the soil and in the aboveground biomass.............. 58
5.3.2.1. Scenario 3: Entire plantation
lifespan.................................................... 58
5.3.2.2.
Scenario 4: Commitment period 2008-2012 only................................ 58
5.3.3.
Scenario 5: Cost of carbon sequestering including market revenues for the
biomass produced
..........................................................................................
59
5.4.
Conclusion
60
Literature
Cited
61
Task
6. Potential Land Base for Short-Rotation Tree Production in Canada................... 62
Literature
Cited
65
Task
7. Afforestation Programs.......................................................................................... 66
7.1.
Introduction.....................................................................................................................
66
7.2.
Experience in the U.S...................................................................................................... 66
7.2.1.
The Pacific Northwest....................................................................................... 66
7.2.2.
The North-Central Region................................................................................. 67
7.2.3.
Northeast.......................................................................................................... 68
7.3.
Experience in Canada...................................................................................................... 69
7.3.1.
Ontario.............................................................................................................. 69
7.3.2.
British Columbia................................................................................................ 70
7.3.3.
Alberta.............................................................................................................. 70
7.4.
Conclusions.....................................................................................................................
71
Literature
Cited
71
General
Conclusion.............................................................................................................. 74
1.1a.
Poplar merchantable yield data available in Canada.......................................................... 5
1.1b.
Willow aboveground productivity data available in Canada.............................................. 6
1.1c.
Poplar and willow aboveground productivity data available in the U.S.............................. 6
1.1d.
Average forage yields obtained from various Canadian regional testing sites...................... 8
1.2a.
Belowground productivity of SRF plantations in North America and Europe at
various
stages of development......................................................................................... 12
1.2b. Belowground carbon content of SRF plantations
in North America and Europe at
various stages of
development......................................................................................... 13
1.3. Rate of soil carbon increase
compared with adjacent agricultural crops for a
Number
of SRF plantations at different developmental stages in both North America
and
Europe...................................................................................................................... 17
2.1. Major insect pests and diseases in SR willow
and poplar plantations................................. 28
3.1. Summary of cropping systems used for the
economic analysis............................................ 38
3.2. Estimates of the costs of production incurred
in SR willow production................................ 39
3.3. Estimates of the costs of production incurred
in SR poplar production................................ 39
4.1. Electricity rates in several Canadian
provinces................................................................... 42
4.2. Estimated cost of electricity for various
biomass feedstocks and selected biomass
cost.................................................................................................................................
43
4.3. Estimated fuel cost of home heating with
electricity, wood pellets or oil, in Québec............. 46
4.4. Ethanol and by-product production from
different raw materials......................................... 48
5.1. Aboveground carbon accumulation per harvest
cycle in willow plantations.......................... 52
5.2. Aboveground carbon accumulation in a 12-year
rotation of hybrid poplar.......................... 53
5.3. Estimated belowground biomass and
corresponding carbon content................................... 55
5.4. Change in soil carbon stock for different
rates of soil organic carbon accumulation.............. 55
5.5. Scenario 1 - Estimated cost of soil organic
carbon sequestration over an SR tree
plantation
life
span............................................................................................................
56
5.6. Scenario 2 - Estimated cost of soil organic
carbon sequestration in SR tree
plantation over
2008-2012............................................................................................... 57
5.7. Scenario 3 – Estimated cost
of sequestering soil organic carbon and carbon in standing
tree
biomass over SR tree plantation life span.................................................................... 58
5.8. Scenario 4 – Estimated cost of soil organic
carbon sequestration in SR tree plantations
over 2008-2012.............................................................................................................. 59
5.9. Scenario 5 – Effects of biomass
market price
on the NPV of SR tree species expressed per Mg of carbon
sequestered......................................................................................................................................
60
6.1.
Total and estimated usable area of Class 4 and 5 agricultural land for energy
crop
production by province and CLI class............................................................................... 63
1.1.
Soil carbon content following harvest of trees.................................................................... 15
A-
1a. Annual breakdown of costs incurred in hybrid poplar
A-
1b. Annual breakdown of costs incurred in SR willow
A-2.
Calculations of cost of carbon sequestration
List of Symbols
CAN $ Canadian dollar
cm centimeter
F.C. Full
economic cost
GJ Gigajoule
– 4.184 kcal
g
gram
ha
hectare – 2.47 acres
kg kilogram
m metre
Mg
Megagram – one metric tonne – 2,200
lbs – 1.1 ton
mm millimetre
MW Mega watt
n.a. not
available
odt oven
dried tonne (metric)
ppm parts per
million- 1 mg L-1
t
one
metric tonne- one Megagram – 1.1 ton
yr year
U.S. $ United
States dollar – 1.5 Canadian dollar
V.C. Variable
costs
1.3.3.
Conclusions
All studies investigating soil
carbon sequestration within SR plantations have examined soil carbon levels at
one point in time rather than over the long-term, or at least over an entire
rotation. Thus, data largely represent static effects of SR plantations on soil
carbon storage rather than more long-term carbon dynamics. Such limitations
substantially hindered the capacity to fully understand the various
interactions occurring in these systems. Hence, before any accurate and
realistic conclusions can be made about the potential for soil carbon
sequestration in SR plantations, more research investigating this key process
is required.
Nonetheless, based on the
limited information available, a number of general conclusions can be made.
From the U.S. studies, it appears that rotation length is a key factor in the
ability of plantations to remove carbon from the atmosphere over the long-term.
The longer the rotation length, the greater the biomass accumulation over time,
and therefore the greater the soil carbon storage potential. Very short
rotations (i.e. less than 10 years) may therefore not lead to soil carbon
sequestration. Hence, if the aim is to sequester carbon, longer rotations may
be required (Schroeder, 1992; Hansen et al.,1993; Grigal and Berguson, 1998).
The Canadian research indicated that SRF
plantations, if properly managed, may be reasonable, additional carbon sinks.
It was shown that SR plantations in southwestern Québec, when grown under soil
conditions with appropriate soil fertility management (i.e. use of inorganic
fertilizers and/or organic amendments), have the potential to increase soil
carbon levels compared with agricultural systems. Consequently, under
unfavourable soil conditions and improper soil fertility management, it may not
be advantageous to grow such crops for the purpose of carbon storage (Zan,
1998).
Therefore, the benefits of SR plantations are more likely
to come from the replacement of fossil fuels, rather than from carbon
sequestration itself, especially if grown on marginal lands. The relatively
short harvest cycle of many plantations limits to a large extent the amount of
above- and belowground carbon storage in these systems.
1.3.4. Suggestions For Future Research
More research investigating soil carbon
sequestration within SR plantations is required. Specifically, there is a
pressing need to pursue further work into:
·
the
continuous monitoring of soil carbon changes over at least several rotations or
longer periods, in order to avoid transient soil carbon dynamics and to provide
a more accurate reflection of long term trends, as well as to verify the
assumption of a linear soil organic carbon increase with time;
·
short- and long-term
effects of coppicing on soil carbon levels, as well as root turnover and
decomposition rates;
·
the
effects of soil fertility management, such as the use of various rates of
inorganic fertilizers and organic amendments on soil carbon levels;
·
the
effect of various plant nutrients (e.g. N, P, and S) on carbon sequestration in
soils;
·
standardizing
methods of analysis to facilitate comparison between studies.
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2.1. Introduction
This section presents information on several
issues related to the production of SRF systems. Short rotation forest
plantation establishment, fertilization regimes typically employed, harvesting
techniques, and the establishment of breeding programs are discussed. Moreover,
environmental issues related to the culture of SRF systems, such as disease and
insect management, concerns about nutrient and pesticide loading to the
environment, water use, soil erosion, and biodiversity impacts are also
reviewed.
2.2. Production Practices of SRF
There is a substantial amount of research data
and production experience available for both SR willow and poplar cultivation.
Much of the willow production information has been developed in Europe, and a
large database on poplar production is available from North America. The two
species are discussed separately due to differences in production strategies.
2.2.1. Willow
2.2.1.1.
Production
Many of the operational constraints for willow
production have been resolved through extensive research in Europe. Sweden has
the largest willow program with 17,000 ha under production. However, the
program in Sweden has recently been scaled down to 500-600 ha yr-1
planted annually (Carter, 1999).
The standard willow production system currently
in use is to grow willow at approximately 12,000-15,000 cph on a 3-4 year
rotation, with a plantation life span of 20-25 years. A twin-row planting
system with paired rows set 0.75 m apart and with 1.5 m spacing is used to
accommodate wheel traffic for machine operations. Mechanized systems of willow
establishment are now well developed with 1.8 m long willow rods being used in
an automated step planter that can cover approximately 0.6 ha hr-1.
After the first year, the crop is coppiced to stimulate shoot production.
Effective weed control remains a challenge but is usually achieved through
pre-site preparation during the previous fall using a broad-spectrum herbicide.
Spring applications during the planting year can include a residual herbicide
such as simazine followed by mechanical cultivation and use of a graminicide
for control of annual and perennial grasses. Fertilization strategies are not
well defined and are difficult to implement because of stand height. In Canada,
the approach proposed by REAP-Canada is to fertilize in late spring, the year
after coppicing, followed by an aerial application of fertilizer in spring, in
the third year of a four-year rotation. This fertilization regime will reduce
expenses, yet provide a reasonable level of fertility for the crop during the
four-year rotation. Another approach proposed is the use of dried sewage sludge
(Labreque et al., 1997).
2.2.1.2. Harvest
The reduction of harvesting costs has been an
ongoing challenge, given that the harvesting phase represents a major cost
component in SRF willow production. Cutting and chipping during one single pass
is the most effective option for harvesting SRF willow coppice. From a storage
perspective, harvesting and chipping during two separate stages may be
desirable but is generally considered to be too expensive. Spinelli and Kaufman
(1997) recently reviewed the current status of willow harvesting technology and
reported a high harvest productivity as well as the availability of reliable
cut-and-chip harvesting equipment. In Europe, the Austoft and Class
harvesters are now in use for large commercial operations.
The Class harvester has been modified
from a conventional forage harvester. The main modification to the conventional
equipment was the requirement of a header (consisting of two disk saws placed
side by side) for harvesting SR willow coppice. The use of a precise planting
pattern designed specifically for the harvest head is also required. The Class
harvester is considered well-suited to farmland having flat, firm soils.
Harvesting losses using the Class harvester are slightly greater than
for the Austoft harvester, but the Class harvester can travel on
roads and generally causes less damage to stools (Spinelli and Kaufman,
1997).
The Austoft harvester is a self-propelled
sugarcane harvester, adapted for SRF harvesting. This harvester is a sturdy,
steel-tracked machine that although is unable to travel on roads, is considered
more reliable (i.e. low downtime) compared with other harvesters. Moreover,
harvesting losses using the Austoft harvester are limited and seldom
exceed 4% of the standing crop (Spinelli and Kaufman, 1997).
A major contributor to further reducing
production costs is the improvement of yields through the adoption of effective
plant breeding programs. Unfortunately, limited research in this critical area
has been carried out in North America. Dr. Louis Zsuffa, a retired plant
breeder at the University of Toronto, was responsible for conducting much of
the willow breeding research in North America. A substantial amount of
germplasm, which Dr. Zsuffa developed, is currently being assessed at the State
University of New York, where a doctoral student is involved in a
willow-breeding project. In Europe however, there are well-established,
long-term willow breeding programs including at the Long Ashton Research Centre
near Bristol, England where 800 new test clones are produced annually.
Similarly, a breeding program at Svalof Weibel in Sweden produces 2,000 new
test clones each year. Seven to ten years are typically required to develop a
new clone. The two European breeding programs produce approximately 3-5 new
commercial willow clones for introduction into Europe each year. The main
objectives of these breeding programs are to improve yields as well as disease
(i.e. Melamspora rust) and insect (i.e. Chrysanalid beetle) resistance
(Carter, 1999).
2.2.2. Poplar
2.2.2.1. Production
Poplar production systems are at a relatively
advanced stage of development. This crop is typically grown at a density of
1,100-1,400 cph. Mechanized planting systems have been developed, but most
commercial crops are hand-planted in order to establish the crop earlier.
Planting frequently occurs at an equidistant spacing to promote cross-cultivation
and good canopy closure. Weed control strategies are similar to those employed
for willow production, but mechanical weeding is more extensive, since canopy
closure does not occur until the third year.
Fertilizer additions in poplar are minimal since
the longer rotations employed (12 years) are less nutrient-demanding than the
shorter rotation cycles used in willow. However, current practices indicate
that band-applied fertilizer after canopy closure can increase performance
(Baldock and Burgess, 1995)
In the Pacific Northwest, insecticides are
generally applied aerially or through the use of drip-irrigation systems when
pest problems first appear.
One problem with poplar productivity is its low
annual growth increment during the initial establishment years. There is
interest in using longer cuttings (e.g. 45-60cm) to improve productivity during
this early establishment period, as well as to minimize weed control
requirements. The use of larger poplar cuttings is likely to be most viable for
lower density plantings destined for solid wood product markets.
2.2.2.2
Harvest
Advances have been made in poplar harvesting
technology, as reviewed recently by Hartsough et al. (1997). Harvesting is
geared to the pulp and paper industry and in some instances, by-products are
targeted for biomass energy production. Currently, harvesting is carried out
with conventional forestry equipment, enabling the production of clean pulp
chips. Typically, the trees are felled and bunched with a “tricycle” or using
an articulated rubber-tired drive tree feller buncher. In recent years,
manufacturers have produced machines known as delimber/ debarker/ chippers,
which combine a chain flail and a disk chipper into a single machine. Engineers
currently believe that the most radical improvement to be made for harvesting
poplar biomass would be the development of continuous-travel felling equipment,
such as that used for willows. However, this would depend on an effective,
economic process to upgrade whole tree chips to pulp quality. One system of
upgrading whole tree chips that has been developed, and referred to as the Masahake
Process, separates whole tree chips into clean chips and residues based on
the physical strength property differences of bark and wood, followed by an optical
sorter (Hartsough et al., 1997). This differentiation, based on chip strength,
is similar to the Paprifer Process that was assessed for separating
willow bark from white chip material (Berlyn, 1995).
Several poplar-breeding programs are underway in
North America. These have been traditionally government funded university based
programs. Some industry led consortiums have also been developed. More recently
in the US, some companies in the Pacific northwest such as Boise Cascade have
decided to set up programs. In the North-Central states, a program is also
based out of the University of Minnesota. The most recently developed breeding
program has been the Western Boreal Aspen Cooperative led by Barbara Thomas,
adjunct professor at the University of Alberta. The program presently focuses
mainly on plant material collection and early field performance evaluations.
Promising material will subsequently be used for developing breeding lines.
In reviewing silvicultural aspects of SR tree
plantations, it is clear that significant progress has been made in converting
SR tree plantations into more commercial, farm-like operations. From a
productivity standpoint, willow plantations are more productive than poplar
plantations and willow biomass can be produced at a lower cost (see Task 3).
This is due to more efficient harvesting operations for willow combined with an
on-the-go cut-and-chip process, and greater willow productivity rates because
of more light interception (i.e. higher planting densities). If a system to
separate bark from wood fibre could be developed through a combination of
engineering and plant-breeding efforts, this may reduce the cost of fibre
delivered to mills, especially for oriented strand board and medium density
fibre board, where a higher tolerance of dark material is considered
acceptable.
Further research needs to be performed on longer
poplar rotations for solid wood products. Moreover, thinning of poplar
plantings needs assessment so that plantations could be used for an early pulp
and paper harvest, followed by a solid wood product harvest.
2.3. Environmental Impacts Associated with
Growing SRF Systems
Extensive research has been
performed on the environmental impacts of SRF systems (e.g. Hopkin and Cheliak,
1995; Hubbes and Lin, 1995; Christian et al., 1994; Crawford, 1995; Biewinga
and van der Bijl, 1996; Sage and Robertson, 1996; Tolbert et al., 1997;
Christian et al., 1998; Kort et al., 1998). All generally agree that SR tree plantations,
if properly managed, can have a positive impact on the environment compared
with agricultural crops. However, negative impacts may occur especially during
the establishment and harvest phases. It is also emphasized that SRF systems
should not be employed as replacements of natural forest habitats.
2.3.1.
Insect and Disease Damage
Short rotation forest systems are prone to a
variety of insect pests and diseases (Hopkin and Cheliak, 1995). However,
damage suffered rarely leads to entire plantation mortality and therefore large
economic losses (Hopkin and Cheliak, 1995). Trees are most susceptible to
injury during the establishment phase of plantations (Dickmann and Stuart,
1983), and resistance varies depending on clones used (Hubbes and Lin, 1995).
In addition, within plantations composed of single clones, insect and pest
damage can be extremely devastating if a poor clone selection is made (Hubbs
and Lin, 1995). Damage can result in mortality, yield loss, and deformation.
Table 2.5 outlines the major insect and diseases affecting willow and poplar
plantations (OMNR, 1993; Hopkin and Cheliak, 1995). Prevention is often
the best measure to undertake against insect damage and diseases. Maintaining a
healthy plantation by ensuring proper growing conditions and effective weed
control is crucial in order to avoid serious injuries. Planting poplar clones
resistant or tolerant to diseases such as septoria stem canker (Septoria
musiva) is important. The planting of clonal mixtures of willow is now being
investigated in Europe as a control strategy against pathogenic diseases, such
as rust. Such clonal mixtures increase the genetic diversity within plantations
rendering them more resistant to disease damage caused by pathogens (Pei et
al., 1997).
Table
2.1. Major insect pests and diseases afflicting SR willow and poplar systems.
|
|
Pest
|
Host
|
Damage
|
Prevention/Control
|
|
Sawfly (Nematus
spp.)
|
Willow foliage
|
Defoliation;
Shoot dieback
|
Selection of
resistant clones
|
|
Imported
willow leaf beetle
(Plagiodera
versicolora)
|
Willow/Poplar
Leaves
|
Skeletonized
leaves;
Holes and
notches in leaves
|
Difficult in
large areas;
Insecticide
spraying in small areas
|
|
Cottonwood
leaf beetle
(Chrysomela
scripta)
|
Poplar leaves
|
Skeletonized
leaves;
Growing shoots
killed
|
Difficult in
large areas;
Insecticide
spraying in small areas
|
|
Septoria
canker
(Septoria musiva)
|
Poplar
shoot/stems
|
Cankering and
death of shoots, branches, stems
|
Harvest early
and replace with resistant stock
|
|
Melampsora
leaf rust
(Melampsora
spp.)
|
Poplar leaves
|
Defoliation;
Decreased
growth/vigour
|
Establish away
from conifers; use wider spacing
|
|
Poplar borer
(Saperda
calcarata)
|
Poplar
shoot/stems
|
Boring and
weakening of stems and roots; tree breakage
|
Remove heavily
infested trees; apply insecticide to stem in early spring and summer
|
|
Poplar-and-willow
borer
(Cryptorhynchus
lapathi)
|
Willow/Poplar
Shoot/stems
|
Weak,
deformed, broken shoots and stems
|
Remove heavily
infested trees; apply insecticide to stem in early spring and summer
|
2.3.2. Pesticide
Loading
There are several levels at which pesticides can have a
negative impact on the environment. First, energy is used to produce,
transport, and apply the pesticides. Of most concern however, are the pesticide
emissions occurring during the application process in the field. As a result of
pesticide emissions during and after application, considerable amounts of
pesticides end up in soil, ground water, surface water and air, posing a great
health risk to ecosystems, wildlife, and humans (Biewinga and van der Bijl,
1996).
Chemical weed control is generally considered essential
when establishing SRF systems, and is often used in addition to mechanical
methods (Sage, 1998). Weed control in established plantations and following a
harvest is usually not required. (Sage, 1998; Perttu, 1998). Severe weed
infestations are often local and can be treated on a local scale (Sage, 1998).
Less competitive shade-tolerant herbs and grasses can colonize within
plantations, however they often do not cause yield reductions (Sage, 1998).
2.3.3. Water Use
Water is fundamental to the process of photosynthesis and
is influenced by many factors. A review of some existing studies in temperate
regions will provide insight into the impact of water use on biomass
accumulation.
In recent years, there has been a significant
amount of research in Sweden indicating that the annual water consumption by
fast growing willow trees creates water deficits (Grip et al. 1989; Persson and
Jansson, 1989). Several models developed from field studies indicate that
annual evaporation exceeds the Penman open water evaporation rate of 430 mm by
between 5% and 40% (Grip et al. 1989; Persson and Jansson, 1989). In a
simulation study, Grip et al. (1989) estimated that 526 mm of water was used
for a normal willow stand producing 12 t ha-1yr-1 of
aboveground biomass. Of this amount, 375 mm was transpired, 56 mm was
intercepted, and 95 mm was evaporated from the soil. The rate of evaporation
was 22% higher than the Penman open water evaporation rate. A biomass crop
producing 12 t ha-1 of biomass would therefore represent a water use
of approximately 44 mm t-1 if 526 mm was used.
Persson and Jansson (1989) estimated a
reasonable range for actual evaporation of willow to be between 370 and 420 mm
during the third year of a willow stand coppiced after the planting year. No
yield data was provided in this study, but assuming a mean annual increment of
10 t ha-1, typically obtained in Sweden, then approximately 40 mm
of water would be required per tonne of biomass.
The yield-limiting potential of water on tree
growth is present even in moderately high rainfall regions of Canada. For
example, in Québec, if 400 mm of water was available for growth (i.e. 40% of
the 1,000 mm average annual rainfall) then the upper yield limits for willow
would be approximately 10 odt ha-1yr-1 (Samson et al.,
1995). Slightly higher amounts of water may be available on higher quality
soils but these would likely not be available for willow production. A clear
demonstration of the yield limiting impact of water can be observed from a
willow study in New York (Abrahamson et al., 1994). This study found willow
yields of 8.9 odt ha-1yr-1 under rainfed conditions
compared with 27.5 odt ha-1 yr-1 obtained under
irrigation.
Hybrid poplars also have large water demands. It
is estimated that consumptive water demand is 1,000 mm ha-1 at
mid-rotation in the north-central U.S. (Hansen et al., 1993). It is evident
from these studies that large-scale plantings of SRF could have a negative
impact on ground water recharge, and significantly increase subsoil water use.
This analysis also clearly demonstrates that SRF productivity is highly
sensitive to water availability. Therefore, efforts to improve productivity
through plant breeding may not be feasible as yields are likely to plateau due
to water-use efficiency restrictions on productivity. For example, with alfalfa
it took a long period of time to replace the leading alfalfa variety (Vernal)
used in the 1950’s by new, improved cultivars. These new cultivars, however,
have only reached yields that are 9% greater than variety Vernal (CPVQ, 1995).
With this C3 alfalfa species, a substantial breeding effort by seed
companies and government research scientists has created a genetic gain of only
0.25 % per year over the past 40 years. It is evident that C3
species, such as fast growing trees will have a more restricted upper yield
potential than more water-use efficient biomass crops such as C4 perennial grasses
(Samson and Chen, 1995).
The impact of SR crops on soil quality depends on several
factors including the crop itself, soil, the land use it is replacing, and
climate (U.S. Congress, 1993). In general, SRF systems lead to a reduction in
soil erosion (U.S. Congress, 1993; Kort et al., 1998) by increasing water
movement into soil, lessening the deleterious effects of water droplets,
intercepting precipitation, and stabilizing soil by their roots and leaf litter
(Kort et al., 1998). Soil structure and aggregate stability were also improved
in SR tree plantations (Tolbert et al., 1997a). Tree plantations are generally
better at reducing erosion than conventional row crops and are similar to
well-maintained pastures. (U.S. Congress, 1993). For instance, in a Danish and
Swedish study, it was found that significantly less soil erosion occurred under
willow compared with wheat production. However, erosion rates under willow were
similar to those occurring under green fallow (Hadders and Olsson, 1996;
Jørgensen, 1996). Poplar plantations have been recommended on slopes subject to
erosion, especially on sides and bottoms of gullies to reduce water flow and
act as a trap for loosened materials (Kort et al., 1998). They have also been
recommended for streambank protection, especially where waterflow can be high
(Kort et al., 1998).
Soil erosion can occur under SR systems (Turhollow et al.,
1985; U.S. Congress, 1993; Hadders and Olsson, 1996; Jørgensen, 1996; Heilman
and Norby, 1998; Kort et al., 1998), particularly in early years of
establishment and following harvest because of lack of soil protection during
these periods (Heilman and Norby, 1998; Kort et al., 1998; Kuch and Crosswhite,
1998). This is often experienced after a forest clear-cut where large increases
in water erosion are seen (Kort et al., 1998). For example, in an Iowa poplar
plantation free from herbaceous vegetation, soil erosion within the plantation
was problematic especially during periods of heavy rainfall (Kort et al.,
1998). Hence, without a constant dense vegetation cover, erosion rates can
increase.
Since growing SRF systems will likely occur on marginal
lands, impacts on soil erosion must be addressed particularly during the
establishment phase since these lands are often easily eroded (Turhollow et
al., 1985; Kort et al., 1998). Site preparation, weed control, and reduced
tillage will be of great importance to prevent negative environmental impacts
caused by soil erosion (GRRBEP, 1986).
Short rotation tree
plantations have minimal potential to cause nutrient loading to the
environment. However, when nutrient loading to the environment does occur, it
is mainly during establishment and harvesting activities, and not during the
main production years.
Nutrient losses associated with leaching,
runoff, and erosion are more likely to occur during plantation establishment
years and following a harvest because of lack of soil protection and absence of
nutrient uptake by the crop (Heilman and Norby, 1998). In some instances,
runoff of nitrogen and phosphorus from SRF systems in the establishment years
can be negligible (Tolbert et al., 1997a). After establishment, potential for
nutrient loss from surface runoff is minimal as the canopy intercepts rainfall
intensity. In a study conducted in the Netherlands, it was shown that both
poplar and willow had low surpluses of residual nitrogen (40 kg ha-1)
compared with annual crops (greater than 100 kg ha-1) such as rape
seed, sugar beet, winter wheat, sorghum and silage corn. Willow and poplar
nitrogen surpluses were comparable to those of grass fallow (Biewinga and van
der Bijl, 1996).
The development of an
extensive root system also plays a significant role in the uptake of nutrients
and minimizing nutrient movement through runoff (Tolbert et al., 1997a). For
instance, willow has been found to be efficient in the uptake of nutrients because
of its well-developed root system (Ledin, 1996). Depth of rooting is also
important in preventing the leaching of nutrients, such as nitrate (Heilman and
Norby, 1998).
When nutrients are lost through harvesting
practices, quantities of nutrients removed vary with yield, species or clone,
and time of harvest (Heilman and Norby, 1998). For instance, in a study
comparing nutrient losses of 6 four-year old cottonwood clones, nutrient
removal from harvest (not including leaf harvest) varied from 95 to 420 kg ha-1
of nitrogen (Heilman and Stettler, 1986). If leaves are included in the
harvest, the quantity of nutrients removed will increase. Therefore, nutrient
removal will also vary depending on the timing of the harvest (affecting
presence or absence of leaves) in the growing season and degree of removal of
leaves from the site (Heilman and Norby, 1998). It has been shown that winter
harvests of plantations improve nutrient retention because leaves are not
removed from the site (Graham et al., 1996).
Nutrient extraction rates are generally lower in
species of longer rotations, such as poplar, since a greater percentage of its
biomass lies within the wood rather than the bark. Leaving bark and fine
branches at the felling site can minimize nutrient extraction from poplar
plantations. Poplars can show significant response to fertilization during the
production cycle. Band application of fertilizer as in the case of row crops
provides for a more efficient use of fertilizer than broadcasted applications
(Baldock and Burgess, 1995).
In willows, shorter rotations are employed and
higher fertilization rates are required since frequent removal of all
harvestable biomass occurs from the site. The increased amounts of nitrogen
fertilizer inputs increase the fossil energy input requirements of willow
compared to poplar. Nonetheless, since willow is an efficient converter of
solar radiation, its energy balance is favourable, having an energy
output/input ratio of 20 (Girouard et al., 1999).
2.3.6.
Biodiversity
Wildlife can either be positively or negatively
affected by SR plantations depending on the way the crop is managed, the
location of the plantation with respect to other land uses, and which land use
it displaces (Wolfe 1993; Christian et al., 1998). If properly designed and
established, such plantations can provide a favourable habitat for wildlife and
serve as effective travel corridors (Wolfe, 1993). For example, a number of
studies have demonstrated that SR systems to provide useful habitat for
wildlife (Christian et al., 1994; Crawford, 1995; Sage and Robertson, 1996;
Tolbert et al., 1997; Christian et al., 1998). In studies conducted in the
Pacific Northwest and upper Midwest, hybrid poplar plantations did provide
habitat for breeding and migrant birds (Tolbert et al., 1997b). Bird species
were found to use hybrid poplar plantations to a greater extent than
agricultural crops, but to a lesser extent than natural forests (Tolbert et
al., 1997b).
Several factors can affect biological diversity
in SRF systems. Major factors include the structural complexity of the
plantation system, plantation age, rotation cycles, harvesting activities,
adjacent land use, and the time scale within which the plantations are managed
(Wolfe, 1993).
In general, the more complex the vegetation structure
within a system, the more diverse the community of animals associated with it.
Therefore, as vegetative structure becomes simplified, so does the community it
supports (Wolfe, 1993). Vegetative diversity therefore plays a critical role in
increasing biodiversity within SR plantations. Short-rotation systems that are
intensively managed have little ground vegetation due to chemical and
mechanical weed control early in the rotation, and shading later on. Such
systems may therefore offer little to increase biodiversity. These plantations
lack the structural complexity that is required for increasing biodiversity,
such as the presence of canopy gaps to encourage other plant growth and dead
trees (Christian, 1997). Conversely, in less intensely managed systems, where
vegetative diversity occurs usually because of incomplete weed control,
increased biodiversity ultimately takes place. For example, in a midwestern
U.S. poplar plantation, a high proportion of small-mammals were found to occur
in portions of the plantation that were poorly established (i.e. other
vegetation/weeds present) whereas mammal communities in the well-maintained
portions had fewer and less diverse species (Christian et al., 1997). In the
midwestern U.S., well-maintained poplar plantations had only 0 to 49% of the
plantation being utilized by birds and mammals (Crawford, 1995). Therefore, in
areas where weed control is very effective, and thus little vegetative
diversity present, the possibility to increase biodiversity is lost (Christian
et al., 1998). Hence, the use of genetically engineered trees to enable
broad-spectrum herbicide use would be expected to provide extremely clean
plantations and low biodiversity potential. This is of particular concern with
the introduction of genetically engineered poplars, which may outcross native
poplar species (Tolbert, 1999).
The use of SRF systems for wildlife is also
affected by plantation age since the habitat offered within a plantation will
change with time (Wolfe, 1993; Sage and Robertson, 1996). In a Minnesota study,
the amount and diversity of breeding birds utilizing young hybrid poplar
plantations was initially similar to those utilizing grasslands and row crops.
However, as the plantations approached canopy closure, successional species
became predominant (Tolbert et al., 1997b). Another, midwestern U.S., study
also demonstrated that shortly after planting poplars, the bird species
frequently observed within the plantations were typically associated with those
observed in open fields. However, between ages 2 and 4 years, a change in bird
species composition had occurred (Hanowski et al., 1997). In a British study,
more migrant bird species were recorded from a 2-year old than a 1-year old
willow plantation after coppice and most resident species selected older willow
or poplar coppice growth (Sage and Robertson, 1996).
Species composition of small mammals also
changes with plantation age. For instance, shrews were found to be absent from
young, well-maintained poplar plantations, but appeared in well-vegetated
patches on both young and older plantations (Christian et al., 1997). In
addition, mammal communities in young plantations were dominated by a single
species generally found in open habitats (Christian et al., 1997). In older
plantations however, a more diverse array of species was present, including
species generally associated with more complex vegetation structures and forest
habitats. However mammals requiring forest habitats were almost completely
absent from older plantations (Christian et al., 1997; Christian, 1997).
Therefore, plantations even late in the rotation will likely harbour species
primarily seen in open habitat but not those associated with forest (Christian
et al., 1997; Christian, 1997; Christian et al., 1994).
Harvesting activities and
rotation cycles may also negatively impact biodiversity. For instance, in the
case where a winter harvest will remove all or most vegetative cover, this will
ultimately leave wildlife with no adequate cover for winter, no protection from
predators, and destroy their nesting ground thus disrupting nesting activities
the following spring.
Biodiversity within biomass plantations is greatly
affected by the surrounding landscape (Christian et al., 1998). As observed in
a study conducted in Ontario poplar plantations, bird communities were
influenced by the surrounding landscape. Forest birds were more abundant in
plantations that were surrounded by natural forest than by those that were not
(Christian et al., 1998). In addition, more species occurred on plantations
located adjacent to both forested and open habitats than on those located in a
less diverse area. In the U.S. Midwest, bird species associated with forest
habitat were also found on plantations in close proximity to forest (Hanowski,
1997). Similarly, species associated with open habitats were more commonly
observed on plantations surrounded by open and agricultural landscapes
(Christian et al., 1998).
In closing, it should be mentioned that another threat to
biodiversity posed by perennial biomass crops is their ability to compete with
the natural flora. In Ontario, introduced potential biomass crop species; black
locust and miscanthus, have escaped into natural areas. Genetic pollution is another
such threat.
2.3.7. Conclusions
Extensive research has been performed on the
environmental impacts of SRF systems. Most evidence suggests that afforestation
of SR tree plantations has a more positive impact on the environment than
conventional agricultural crops because of limited soil erosion, decreased
pesticide impacts and fertilizer applications, and increased biological
diversity. However, increasing the intensity of management of SR plantations
through the establishment of larger-scale operations, increased chemical use,
and the use of genetically engineered crops may eventually lead to a loss of
these potential positive impacts.
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Crawford, S.L.
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Graham, R.L., Downing,
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Grip, H., Halldin, S.,
Lindroth, A. 1989. Water use by intensively cultivated willow using estimated
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D., Stokes, B. 1997. Harvesting systems for short-rotation woody crops.
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Heilman, P.,
Norby, R.J. 1998. Nutrient cycling and fertility management in temperate
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Hopkin, A.A., Cheliak,
W. 1995. Pest problems on immature poplar and willow in Ontario and their
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Hubbes, M., Lin, D.
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Collins, M., Ditsch, D. 1998. A review of the soil erosion potential associated
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Kuch, P.J.,
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Teodorescu, T.I., Daigle, S. 1997. Effects of plantation site and wastewater
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Hunter, T., Royle, D.J. 1997. Variation in populations of Melampsora willow
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Sage, R.B.,
Robertson, P.A. 1996. Factors affecting songbird communities using new
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Y. Chen. 1995. SRF and the Water Problem. In: Proceedings of the Canadian
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1999. Personal communication.
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Hanowski, J., Hoffman, W., Schiller, A., Christian, D., Lindberg, J. 1997b.
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Biomass Conference of the Americas. Montréal, Québec, Canada. August 24-29
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Jr., Shen, S.S., Oamek, G.E., Heady, E.O. 1985. The potential impacts of
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1999. Personal communication.
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Government Printing Office. OTA-BP-E-118. 71 pp.
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1993. Potential impacts of energy-dedicated biomass production on wildlife
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Office of Technology Assessment. April 30, 1993.
Task 3: Costs of
Production
3.1. Introduction
Costs involved in growing hybrid poplar and
willow managed under SR systems were estimated using BIOCOST-Canada and BIOCOST-USA
softwares. Default parameter values were adjusted to mimic as closely as
possible the commercial cropping practices and the Canadian cropping regime
environment. Once the default parameters were established, the same set of
cropping practices was used for different regions in Canada, for each crop.
Any variation in total cost was a result of annual productivity variations
among regions.
3.2. Assumptions
Using 1995 dollars, production costs per ha are
estimated for each year of a plantation lifespan and discounted to present
value using a 10% discount rate. Similarly, expected harvestable biomass yields
over the entire plantation lifespan are discounted to present value and used to
determine the present value of cost per odMg. Estimates for SR willow are
computed using BIOCOST-Canada while estimates for hybrid poplars are
generated by BIOCOST-USA. The latter estimates were adjusted to be
expressed in Canadian dollars and metric units. Detailed assumptions used by
the softwares are outlined in Girouard et al. (1999) and in Walsh and Becker
(1996).
The main parameters used to conduct the current
study are presented in Table 3.1. Hybrid poplar default values and cropping
practices are based on averages of commonly used practices in Canada and in the
U.S. Short-rotation willow values are based primarily on practices carried out
in research and demonstration sites in southwestern Québec (Samson et al.,
1995). For both crops, it is important to note that variations exist within
specific studies and commercial applications, and that the estimates developed
in this study aim at providing an order of magnitude of costs incurred in
growing SR tree species rather than providing estimates for specific field
locations.
Both hybrid poplar and willow are assumed to be
established on farmland, where no brush removal is necessary. A broad-spectrum
herbicide is applied to the sites in the fall, prior to planting and plowing.
Disking may be performed in the fall for hybrid poplar, and preferably in the
following spring for willow. Hybrid poplar planting is performed manually using
25-cm long cuttings and at a spacing of 2.5 m by 3 m (1,389 trees ha-1).
Willow 30-cm long cuttings are mechanically planted at a spacing of 0.92 m by 0.92
m (11,800 trees ha-1). Default values for hybrid poplar cutting and
planting costs are 25 cents (¢) and 16 ¢ cutting-1, respectively.
Default values for SR willow are 5.0 ¢ cutting-1 for the planting
operation and 2.0 ¢ cutting-1 for the cuttings.
Weed control after planting hybrid poplar
involves one application of Simazine and three passes of soil cultivation. In
addition, one application of Linuron herbicide is performed in year 2 and 3,
along with two and one passes of soil cultivation, respectively. Weed control
in SR willow after planting is accomplished by spraying Simazine and Assure
herbicides, and with three passes of soil cultivation in the establishment
year. No weed control measures are required in the years thereafter. The use of
insecticides on either crop is not considered in this study.
Fertilization requirements in hybrid poplar
plantations appear to be relatively small compared with annual agricultural
crops and SR willow. Since fertilization is site-dependent, it is sometimes not
required. Poplar production default values from BIOCOST-USA are used in
this study and assume fertilizer applications of 83.5 kg of nitrogen (N), 22.5
kg phosphorus (P), and 39 kg of potassium (K) per ha over a 12-year harvest
cycle. Fertilization requirements for SR willow are currently under
investigation and are very site-specific. This study assumes applications of
200 kg N, 47 kg P and 147 kg K per ha over each 4-year harvest cycle of a
willow plantation (Samson et al., 1995).
Hybrid poplar is assumed to be harvested after
12 years of growth, and involves felling and bunching of the trees, skidding of
the bunched trees to the edge of the field, and on-site chipping, with direct
loading onto a van (Walsh and Becker, 1996). Willow is harvested every 4 years
with a self-propelled direct chipping harvester. Both crops are transported to
a mill located within a 60-km radius. Transportation costs are estimated to be
$11.47 odMg-1 based on a study by Girouard et al. (1998). Hybrid
poplar is replanted after each harvest, whereas willow is replanted after 5
harvest cycles (a total of 20 years).
|
Table 3.1. Summary of cropping systems used for the
economic analysis.
|
|
Activities
|
Hybrid Poplar
|
Willow
|
|
Soil
Preparation
|
Plowing/disking
|
Plowing/disking
|
|
Cuttings
|
25
cm long, $0.25 cutting-1
|
30
cm long, $0.05 cutting-1
|
|
Spacing/Density
|
2.5
m x 3 m / 1389 trees ha-1
|
0.92
m x 0.92 m / 11800 trees ha-1
|
|
Planting
|
Manual
|
Planter
|
|
Chemical Weed
Control
|
-
1 application in
the fall preceding planting (Roundup)
-
1 applications in
the planting year (Simazine)
-
1 application in
years 2 & 3 (Linuron)
|
-
1 application in
the fall preceding planting (Roundup)
-
2 applications in
planting year (Assure and Simazine)
|
|
Mechanical
Weed Control
|
-
3 times in the
planting year
-
2 times in year 2
-
1 time in year 3
|
-
3 times in the
planting year
|
|
Insecticides
|
None
|
None
|
|
Fertilization
|
83.5-22.5-39
kg ha-1 cycle-1
|
|
|
Custom Harvest
|
Feller,
skidder, buncher, chipper
|
Direct
chipping (Class-Jaguar)
|
|
Transportation
to Mill
|
60 km radius /
$11.47 odMg-1
|
60 km radius /
$11.47 odMg-1
|
|
Harvest Cycle
|
|
4 years
|
|
Plantation
Lifespan
|
12 years
|
20 years
|
3.3. Production Cost Estimates
This study provides two sets of production cost
estimates for each crop: one only includes direct variable cash expenses, while
the other provides the full economic cost. A provision for land rental (or
repayment) is not included in either set, as a result of the difficulty in
estimating an accurate value for the various land-uses in each region investigated.
Estimates based on variable cash costs only
include expenses related to cuttings, chemicals, fertilizers, fuel, repairs,
custom harvest, and transport of chips to a mill. The estimates are delivered
cost estimates at the mill gate and represent the minimum market price required
by tree growers for the chips to cover variable cash expenses. Estimated
delivered costs are presented in Table 3.2 and 3.3, and more detailed
information can be found in Appendix 1. As previously mentioned, cropping practices
are assumed to be constant across the regions and variations in delivered cost
estimates are the result of variation in expected yields. In response to
favorable growing conditions, the lower mainland of British Columbia has the
lowest cost by region, followed by central Canada.
|
Table 3.2. Estimates of the costs of
production incurred in SRF willow production.
|
Canada
|
Yield
Range
odMg ha-1yr-1
|
Variable Costs Only
($ odMg-1)
|
Full
Economic Costa
($ odMg-1)
|
Atlantic Provinces
|
5 - 10
|
64-92
|
78-116
|
|
Québec
|
7 - 12
|
57-82
|
69-102
|
|
Ontario
|
7 -12
|
57-82
|
69-102
|
|
Prairie
Provinces
|
2 - 6
|
92-106
|
115-134
|
|
|
10 - 15
|
50-64
|
60-78
|
a excludes land rent
Table 3.3. Estimates of the costs of
production incurred in SRF poplar production.
|
Canada
|
Merchantable
Yield Range
odMg ha-1yr-1
|
Variable Costs Only
($ odMg-1)
|
Full
Economic Costa
($ odMg-1)
|
Atlantic Provinces
|
2 – 6
|
91-115
|
127-164
|
|
Québec
|
2.5 – 7
|
82-112
|
112-160
|
|
Ontario
|
2.5 –7
|
82-112
|
112-160
|
|
Prairie
Provinces
|
1- 5
|
104-120
|
146-173
|
|
British
Columbia (lower mainland)
|
9 – 12
|
62-73
|
80-97
|
a excludes land rent
Full economic costs estimated in this study
include the variable cash expenses previously computed in addition to fixed
cash costs (overhead, taxes, interest payments) and the cost of owned resources
(producer's own labour, equipment depreciation, and the opportunity cost of
capital investments). Typically, farmers place more emphasis on variable cash
expenses when making planting decisions since their resource set remains fixed
in the short-term. Long-term survival of the farm nonetheless requires that
returns from farming activities cover all cash expenses, provide a return for
the farmer’s labour, as well as allow for capital replacement, land repayment,
and a return on the farmers investment.
The gross margin per ha (difference between
market returns and variable cash expenses), provides an actual estimate of how
much money is available to cover fixed cash costs and cost of farmer’s owned
resources. In Canada, this value varies substantially and is dependant on
land-use, the nature of farming activities (i.e. extensive agricultural
cropping in the Prairies versus more intensive farming in the eastern Canada),
and farm support programs in place. It is beyond the scope of this study to
estimate contribution margins by region and land-use in order to develop
delivered cost estimates for hybrid poplar and willow. Rather, in this study,
these values are estimated by computing the full economic cost of growing
hybrid poplar and willow, as previously described, while excluding any
allocation for land opportunity cost. These values can be regarded as estimates
of maximum delivered costs that could be encountered in a practical situation.
Table 3.2 and 3.3 present these estimates, and further details are found in
Appendix 1. As a rule of thumb, full economic cost estimates computed in this
study are 24% higher than variable cost estimates for willow and 40% higher for
hybrid poplar. The higher biomass productivity of willow reduces the effect of
fixed charges on an odMg basis.
3.4 Conclusion
Using estimates from variable costs and the fill economic
costs, the delivered cost of hybrid poplar was computed to vary between $82 and
$160 odMg-1 in central Canada, with lower values in the British
Columbia lower mainland. Similarly, delivered cost of willow is estimated to
vary between $82 and $102 odMg1 in central Canada, with lower values
also in the lower mainland of British Columbia.
Literature Cited
Girouard,
P., Walsh, M.E., Becker, D.A. 1999. BIOCOST-Canada: A new tool to evaluate the
economic, energy, and carbon budgets of perennial energy crops. In: Proceedings
of the Fourth Biomass Conference of the Americas, Oakland, Ca. August 29 -
September 2, 1999. In press.
Girouard,
P., Samson, R., Zan, C., Mehdi, B. 1998. Economics and carbon offset
potential of biomass fuels. Draft Report. Contract awarded through
Environment Canada’s Environmental Program and funded by the Federal Panel on
Energy Research and Development (PERD). Contract 23341-6-2010/001/SQ.
Samson, R., Girouard, P., Omielian, J., Chen, Y.,
Quinn, J. 1995. Technology evaluation and development of SRF for energy
production, Final Report. Report completed under the Federal Panel on
Energy Research and Development (PERD) for Natural Resources Canada and
Agriculture Canada. Contract 23440-2-94933/01SQ.
Walsh, M., Becker, D. 1996. Biocost: A software
program to estimate the cost of producing bioenergy crops. Proceedings of the
Seventh National Bioenergy Conference: Volume 1, September 15-20, Tennessee.
Pp. 480-486.
Task 4: Industrial Use and Market Returns
4.1. Introduction
The development of SR tree species is driven by
two main factors:
1. the limited amount of
natural forest resources available to meet forecast growth increases in
traditional solid wood and pulp and paper markets;
2. the need to develop a
large supply of biomass to enable bioenergy to capture a significant share of
the Canadian energy market.
Fibre applications from SR tree species, mostly
with hybrid poplars, are already in progress in some regions of Canada.
However, as a result of poor economics, SR tree species grown for the Canadian
energy market, are only at a demonstration stage, although internalizing
environmental costs associated with fossil fuel use may open a window of
opportunity for biomass in the future. Short rotation tree plantations may have
a difficult role to play in bioenergy applications, as wood residues and
agricultural residues will likely increase in importance in this industry as
they represent the lowest cost bioenergy feedstocks. As well dedicated
herbaceous feedstocks such as perennial grasses have a lower cost of production
per gigajoule (GJ) of energy and can be used for some of the same energy
applications (Girouard et al., 1995). Furthermore, the fibre value of SR tree
plantations is substantially higher than energy markets. The following section
outlines some of the main potential fibre and energy markets for SR tree
species, and the potential market price required for these crops to be cost
competitive with current feedstocks, without any credit for GHG emissions
abatement.
4.2 Electricity Generation
Despite the relative abundance of biomass
material (i.e. forest and agricultural residues, peat, municipal solid waste
(MSW)), it has been shown to represent less than 1% (approximately 1,000
megawatts (MW)) of the total electricity generation capacity and only 0.5% of
electricity production in Canada (Rouleau, 1995). Most of this electricity
originates from cogeneration facilities installed in pulp and paper mills. With
the exception of wood mill and logging residues, electricity generation from
traditional sources has been less expensive in the past. For instance, in
1993, the average resident in Canada was estimated to pay 8.26 cents per
kilowatt hour (¢ kWh-1), while electricity generation from biomass
sources, other than forestry residues (i.e. peat, MSW, straw and energy crops),
was estimated to range between 8.7 and 13.5 ¢ kWh-1 for direct fired
technology (Rouleau, 1995). Electricity from mill and logging residues was
estimated to range between 5.5 and 8.6 ¢ kWh-1.
In general, provinces which can substantially
rely on hydro-electrical potential (Québec, Manitoba, British Columbia and
Newfoundland) offer a more hostile environment for biomass power than those
relying heavily on coal (i.e. Ontario, Saskatchewan, Alberta, New Brunswick and
Nova Scotia). It is also in these coal-dependent provinces that biomass could
be most effective in reducing carbon emissions resulting from electricity
generation. It is beyond the scope of this study to factor in the impact of
the deregulation occurring in the North American electricity market for
biomass-derived electricity, however this issue certainly requires further investigation.
From a study conducted by Rouleau (1995), the provinces
which have been projected to have the greatest potential for biomass power by
the year 2010 are Alberta, Ontario, Saskatchewan, New Brunswick, Nova Scotia
and Newfoundland. Residential and industrial electricity rates for these
provinces in 1993 are presented in Table 4.1. Long-term trend values estimated
from time series data from 1982-1993 (Rouleau, 1995) are also presented.
|
Table 4.1. Electricity rates in several Canadian
provinces.
|
|
Provinces
|
Residential Electricity Ratesa
¢ kWh-1
|
Industrial Electricity Ratesb
¢ kWh-1
|
|
|
1993
|
Estimated Long-Term Trend
|
1993
|
Estimated Long-Term Trend
|
|
Newfoundland
|
8.64
|
8.1
|
5.04
|
5.7
|
|
Nova Scotia
|
9.58
|
8.6
|
5.58
|
5.5
|
|
New Brunswick
|
7.69
|
7.5
|
4.65
|
4.8
|
|
Ontario
|
10.01
|
7.2
|
6.80
|
5.2
|
|
Saskatchewan
|
8.39
|
7.2
|
4.80
|
5.1
|
|
Alberta
|
7.12
|
6.3
|
4.53
|
3.9
|
|
Average
|
8.57
|
7.5
|
5.23
|
5.0
|
Adapted
from Rouleau (1995).
a Residential rates
based on monthly consumption of 1,000 kWh
b Industrial rates based
on monthly consumption of 3,100,000 kWh
As presented in table 4.1, biomass-derived
electricity must be produced for a total cost of 6.3 to 8.6 ¢ kWh-1 to
be considered as being competitive in the residential market. In order to fall
into this range, mill and logging residues ranging in price from $16 to $35
odMg-1, must be employed either in a conventional direct fired
technology, or in a currently-developing gasification technology (Table 4.2).
Estimates for these technologies are computed for plant sizes of 25 and 50 MW.
|
Table 4.2. Estimated cost of
electricity for various biomass feedstocks and selected
biomass cost.
|
|
Biomass
|
Transportation Distance
|
Cost
|
Direct Fired Technology
|
Gasification Technology
|
|
|
Km
|
$ odMg-1
|
¢ kWh-1 b
|
¢ kWh-1 b
|
|
|
|
|
25 MW
|
50 MW
|
25 MW
|
50 MW
|
|
Mill Residues
|
40
|
15.79
|
5.5
|
6.7
|
6.4
|
6.3
|
|
100
|
19.28
|
5.9
|
7.0
|
6.7
|
6.5
|
|
Logging
Residuesa
|
40
|
31.38
|
7.4
|
8.3
|
8.0
|
7.4
|
|
100
|
35.21
|
7.8
|
8.6
|
8.4
|
7.7
|
|
Peat sods
|
40
|
84.92
|
13.0
|
12.7
|
13.0
|
10.9
|
|
100
|
89.89
|
13.5
|
13.1
|
13.4
|
11.3
|
|
MSW
|
40
|
47.14
|
10.9
|
11.0
|
11.0
|
9.5
|
|
100
|
51.47
|
11.4
|
11.5
|
11.4
|
9.8
|
|
Straw
|
40
|
39.37
|
8.7
|
9.1
|
8.8
|
7.8
|
|
100
|
45.53
|
9.2
|
9.8
|
9.4
|
8.3
|
|
Energy Crops
|
40
|
56.38
|
10.4
|
10.7
|
10.5
|
9.1
|
|
100
|
60.21
|
10.9
|
11.1
|
10.9
|
9.4
|
Adapted
form Rouleau (1995).
a road side
b cost of electricity
is set to provide a return equivalent to the weighted average cost of capital
employed to finance the project.
Gasification technology, though still at a
developmental state, is viewed by many experts as the most promising technology
for reducing long-term costs of biomass-derived electricity generation. In an
analysis conducted in 1992, the U.S. Department of Energy predicted that
further improvements in direct-fired technology may result in only minor cost
reductions (less than 10%). However, reductions may be significantly higher, in
the order of 25%, for the gasification process (USDOE, 1992). A scenario for
gasification technology was developed by Rouleau (1995) where plant capacity
was increased to 103 MW, gasifier efficiency to 85%, and capital cost reduced
to $1300 MW-1. In Table 4.2, when plant capacity is either 25 or 50
MW, gasifier efficiency is at 80% and capital cost ranges between $1,996 and
$2,306 MW-1. The former scenario assumes that energy crop biomass is
delivered to the plant for $48 odMg-1. The resulting cost of
electricity produced is 7 ¢ kWh-1, a 25% cost improvement over the
50 MW scenario presented in Table 4.2 (energy crops).
Assuming that logging residues, such as
presented in Table 4.2, produce cost competitive electricity in the future, and
that improvements in gasification technology warrant the use of biomass priced
at $48 odMg-1, the competitive market price range for biomass
produced from SR tree species is estimated to be $30-$50 odMg-1.
4.3. Space and Process Heat Energy Applications
In northern Europe, one of the primary markets for wood
chips from SR willow plantations is as a fuel source for district heating
systems. In Canada, district heating systems are currently not widely
available. The best opportunity for using plantation-grown material for space
heating would be to grow material for small- to medium-sized biomass combustion
installations in rural areas. An example of the potential scale of this
opportunity can be observed from Austria’s development of this technology,
which has 13,000 small- to medium-sized automatic wood chip furnaces (Grubl,
1995).
In Canada, typical medium-sized biomass heating
systems are in the 5-15 MW range and are currently burning sawdust or bark from
the wood processing industry. The company KMW of London, Ontario has
been the major player in this market, with approximately 75 wood combustion
systems installed and 8-10 new installations each year. Approximately 20
systems have been installed in institutions such as schools and hospitals.
Concerning smaller-scale biomass heating
systems, Grovewood heat of Little York, Prince Edward Island, has installed
approximately 150 wood chip heating systems in the 75-300 kW range for heating
enterprises such as hog farms, fish farms, greenhouses, garages, motels, as
well as smaller wood industries. Approximately 15 new combustion systems are
being sold each year. The equipment typically consists of a wood chip hopper,
combustion and boiler. Two combustion systems are often set up in tandem which
allows the operator to run one burner at high capacity during periods of low
heat demand such as the spring and fall shoulder heating seasons (EOMF,
1994). These types of units are ideal for farmers that could grow their own
wood fuel for farm energy purposes. This would help reduce material transport
costs to more distant facilities.
Biomass combustion systems must compete with
conventional energy sources such as oil, natural gas and electricity. SRF
willow plantations for fuel production can easily compete with these energy
sources on a fuel cost basis, however, wood fuel burning systems have a higher
capital cost and somewhat lower energy conversion efficiencies than those of
conventional energy systems. An analysis of fuel costs for
residential-delivered conventional energy sources for heating oil, natural gas
and electricity was $9.27, $7.14 and $16.61 gigajoule-1 (GJ-1)
respectively in Quebéc while SR willow was $3.20 - $4.82 GJ-1
delivered to a plant and $2.82 - $4.46 GJ-1 when used on site
(Girouard et al., 1995). However automated biomass systems typically costs 2- 4
times as much as oil burning systems for example, mainly because of the cost of
the fuel storage and handling components of biomass systems (McCallum, 1993).
These additional capital costs must be amortized by the savings achieved from
the lower cost of biomass fuels.
With this market, the main problem for SR
plantations is the low cost of wood residues for the heating systems currently
available in most regions. For example, in Prince Edward Island, sawdust is
sold for $23 odt-1, while wood chips are selling for $40-$52 odt-1,
with sawmill chips at the lower end of the range and whole tree chip prices at
the upper end of this range (Court, 1999). However wood residue availability
concerns are rising and it is reasonable to expect that SR willow plantations
used on farms could compete with wood chips. The current cost of production of
SR willow wood chips is $58-$85 odt-1 (Girouard et al., 1998). This
cost is reduced to approximately $49 -$72 odt-1 if used on-site through
reduced transportation costs.
Of all the biomass energy applications currently
available, the direct combustion of green wood chips for space and process heat
in small- to medium-sized commercial heating systems may be the most viable
energy entry point for SR willow plantations. The advantages of this end use
are the relatively low capital cost of the energy conversion systems and the
proximity of the market for the material. The main barriers to this technology
are the low cost of fossil fuels and the existing supply of lower cost wood
residues. Nonetheless, this could be a promising strategy for GHG abatement in
the future as fossil fuel prices increase and wood residue supplies diminish.
4.4.
Pellet Fuel
The use of wood fuel pellets for home-heating
purposes is slowly gaining in popularity both in North America and Europe. From
1995-96 to 1997-98, sales of bagged fuel pellets increased from 595,000 tonnes
to 628,000 tonnes, in North America. Canada is expected to export approximately
100,000 tonnes of bulk pellets to European countries in 1999, which is seen as
the main growth area over the next several years. Despite the competitiveness
of the North American home fuel heating market, pellet stove sales still
managed an 11% increase in sales in 1997-1998 after two years of declining
sales (Pellet Fuels Institute, 1998). Wholesale pellet selling prices vary by
region. In western Canada, pellet producers report prices of $110-$121 (CAN
$165-$182) t-1, while central and eastern Canadian producers report
prices of $121-$138 (CAN $182-$207) t-1 for domestic sales. Prices
for bagged pellets are higher in the U.S. with US$ 110-$129 (CAN 165-$194) t-1,
US$ 105-$116 (CAN $158-$174) t-1, and US$ 99-$105 (CAN $149-158) t-1
in the northeast, northwest and mid-western U.S., respectively (Pellet Fuels
Institute, 1998).
Sawdust and wood shavings are the main
feedstocks for pellet production. As residues are becoming less available and
more expensive, there is increased concern about the future competitiveness of
the pellet fuel industry. Tree bark is seen by many as the upcoming raw
material for pellet production, however, the increased ash content of this
material causes slag formation in most pellet stoves that are currently on the
market. The only pellet stove that can potentially handle bark burning has been
recently developed by Dell-Point Technologies (Québec) in partnership
with Natural Resources Canada. This close-coupled gasification technology
pellet stove also has an overall efficiency of 81-87%, which compares
favourably to more modest efficiencies of 35-70% attained by most stoves
currently on the market (Samson et al., 1999).
In the short- to medium-term, wood pellets
produced from SR tree species may likely be used as a substitute to other
forest residues for stoves currently installed and incapable of handling higher
ash content fuels, such as bark. In the long run, the likely increased use of
new technology pellet stoves will improve the role of bark in the market and
may limit the potential market value of SR tree species for pellet
manufacturing. Bark is a widely available raw material and unless demand for
this commodity increases substantially in the future, it will likely remain a
fairly low-cost feedstock.
Recent development in pellets manufactured from
a potential herbaceous energy crop, namely switchgrass (Panicum virgatum),
suggests that this feedstock may also play a significant role in the future of
the pellet industry. REAP-Canada, Dell-Point Technologies and
Natural Resources Canada are currently optimizing the pellet production process
for switchgrass and early results show that pelleting throughput can be
increased by two- or three-fold compared with wood residues. In addition,
drying of the material is unnecessary, further contributing to a reduction of
energy and capital costs over wood residues and bark. Switchgrass is 40% less
expensive to grow than SR tree species, such as willow (Girouard et al., 1995).
Preliminary research on the pelleting of SRF willow indicates higher throughput
rates compared with conventional hardwood materials. This may be a result of
the relatively weak fibre properties of these species.
A survey involving U.S. wood pellet producers
has indicated that the average cost of wood residues and drying for pellet
manufacturing is $46.29 odMg-1 (Council of Great Lakes Governors,
1995). Recent discussions with pellet manufacturers have indicated that some
pellet manufacturers in the northeast U.S. are presently paying up to $45 odMg-1,
prior to drying costs, to access forest residues. In eastern Canada, pellet
manufacturers are apparently paying from $20 to $30 for forest residues.
Although regional prices vary with supply and demand, a market price of $30-$50
odMg-1 for SR poplars and willows for sale to the pellet industry is
used in this study. This range is thought to be applicable in the future since
bark, and potentially switchgrass, will enter that market.
The fuel cost associated with heating a 2,000
square foot (ft2) home in the Montréal region using wood pellets has
been recently estimated (Samson et al., 1999). Table 4.3 indicates that current
wood pellets burned in the newly released high efficiency Dell-Point
Technologies pellet stove can compete, on a fuel cost basis, with
electrical heating and heating oil in Québec, at 35 cents per litre (¢ L-1).
More details are found in Samson et al. (1999).
Overall, the attractive retail price of wood
pellets indicates that this market could be an interesting high-value market
for SRF willow. Ash content of SRF willows is about 1% - 1.5%, which is lower
than switchgrass or bark.
|
Table 4.3. Estimated fuel cost of home heating with
electricity, wood pellets or oil, in Québec.
|
|
|
Electricity
|
Pellets
|
Heating Oil
|
|
Fuel Cost
|
5.97
¢ kWh-1
|
$180
t-1
|
35
¢ L-1
|
|
Raw Fuel Cost
after taxes
7% GST,7.5%
TVQ.
|
|
|
40.26
¢ L-1
|
|
Cost/GJ
|
$19.24
|
$10.45
|
$10.53
|
|
(95%
electricity, 85% pellets, 85% oil)
|
$20.25
|
$12.29
|
$12.39
|
|
Cost to heat a
new, detached, 2,000 ft2 home in Montréal
|
$2025
|
$1229
|
$1239
|
Source: Samson et al. (1999).
Note 1. Pellets are assumed to have an energy
content of 19.8 GJ t-1, electricity 3.6 MJ kWh-1 and oil
38.2 MJ L-1 (Natural Resources Canada, 1997).
Note
2. The analysis does not include capital costs associated with equipment.
Note
3. Heat requirement of home is 100 GJ (Natural Resources Canada, 1997).
4.5.
Cellulosic Ethanol
The production of fuel grade ethanol in North
America mostly relies on grain corn as a source of sugar for fermentation. The
process of converting corn, or other starch-based materials, into ethanol is a
well-proven technology at the commercial level, but requires financial
incentives from governments to compete on a cost basis with relatively
inexpensive gasoline. Ethanol production nonetheless offers the benefits of
diversifying the farm economy and replacing mostly imported fossil fuels. With
proper corn cropping practices and state of the art conversion technology, corn
ethanol can contribute to reducing greenhouse gas emissions (Wang et al.,
1999).
Lignocellulosic materials such as wood and
grasses have long been identified as lower cost feedstocks that could be used
for ethanol production. Although converting these feedstocks into alcohol has
been known to be feasible since the early 19th century, when it was
discovered that wood cellulose could be dissolved in concentrated sulfuric acid
and converted to sugars (Klass, 1998), large commercial production was never
found to be economical, except in war times. Lignocellulosic materials are
made of crystalline and amorphous cellulose, amorphous hemicellulose, and
lignin binder. The difficulty encountered in maximizing ethanol yields from
the cellulose component, and the difficulty of fermenting the sugars from the
hemicellulose component, have contributed to non-economical ethanol yields from
these feedstocks in the past several decades (Klass, 1998).
Research efforts initiated in the mid-1970’s in
Canada and the U.S. are nonetheless beginning to show promising signs by the upcoming
construction of demonstration plants in several locations across North
America. In Canada, Iogen Corporation in partnership with Petro-Canada
and the Canadian government, are planning to begin construction of a 50 odMg
day-1 capacity lignocellulosic-ethanol demonstration facility. The
objective pursued by Iogen Corporation during its 25-year research and
development program, is to develop a conversion process that is similar in cost
to that of grain corn, but using raw materials delivered to conversion
facilities for approximately one-third to one-half of the average market price
of corn. Fuel grade ethanol could then eventually be produced at a
cost-competitive price with gasoline, which is difficult to achieve with corn
as the conversion technology has nearly reached full maturity.
Estimating a competitive market price for
lignocellulosic feedstock destined to ethanol production is relatively
difficult since no commercial operations have yet been constructed.
Nonetheless, delivered price in the order of $30-$40 odMg-1 is often
mentioned by Iogen Corporation as being in the relevant range. In the
U.S., the goal of the U.S. Department of Energy is to achieve fermentation
ethanol costs in nominal dollars of about US$ 0.16 L-1 by the year
2020 with lignocellulosic feedstocks. This will require raw materials to be
delivered at conversion facilities for approximately US$ 30 odMg-1
(Klass, 1998). In Canadian dollars, the equivalent would be approximately $45
odMg-1. Based on these values, the competitive market price of SR
tree species for the ethanol production market is estimated to vary between
$30-$45 odMg-1. Potential ethanol production and by-products for
different raw materials available in Canada are presented in Table 4.4.
|
Table 4.4. Ethanol and by-product production from
different raw materials
|
|
Feedstock
|
Ethanol Production
(L odMg-1)
|
By-Product Available for Sale
|
|
Grain
Corn
|
450a
|
Distilled
dried grains: 390 kg odMg-1
|
|
Wood/Herbaceous
Biomass
|
340b
|
Electricity/Steam
from lignin: 1.1 kWh L-1
|
a Dry milling process; commercial production.
b Estimated production
in commercial operations. Wood feedstocks may produce slightly less ethanol per
tonne of raw material than herbaceous crops but greater quantities of
by-product electricity/steam.
4.6. Pulp and Paper Production
The forest sector plays a significant role in the Canadian
economy as forests cover 45% of Canada's land base. It contributed $20.6
billion to the Canadian Gross Domestic Product (GDP) in 1996, out of a total of
$680.9 billion, and employed (directly or indirectly) 1 in 16 people (Natural
Resources Canada, 1997). Moreover, Canada is the world’s largest exporter
of forest products. In 1996, forest product exports contributed $32 billion to
Canada's balance of trade.
Maintenance of the forest sector’s important
role in the Canadian economy requires significant adjustments, some of which
are already being implemented. For instance, there is general consensus that
long-term growth of the sector would involve reduced reliance on the production and
export of commodities (i.e. lumber, woodpulp, and newsprint); products that
have price as the main determinant of sales. Rather, emphasis should be placed
on the development of higher-value added products, such as panels and composite
materials, that will generate greater economic activity (GDP, employment, etc.)
per volume of harvested wood (Natural Resources Canada, 1997).
Similarly, the Canadian Pulp and Paper Sector,
which contributed $9.85 billion to the national GDP in 1996, has historically
relied on two main export commodities, namely newsprint and woodpulp.
Traditional comparative advantages, such as the readily accessible, abundant,
economical, high-quality forest resource and the low-cost electrical energy
allowing Canada to be competitive in these markets, are presently on the
decline (Doering, 1997). Several factors account for this industry’s loss of
competitiveness on the world market including the adoption of forest
conservation policies, the long-term rising cost of wood, and the emergence of
new low-cost suppliers of fibre and pulp, mostly from countries in the Southern
Hemisphere. These countries enjoy more favourable growing conditions, which
contributes to reducing the cost of growing the wood, especially when SR tree species
such as eucalyptus are used. Moreover, many of these countries are now capable
of providing the necessary socio-economic infrastructure for the pulp and paper
industry to develop.
Several strategies are being implemented to ensure the
long-term viability of the Canadian pulp and paper industry. One such strategy
allows for better control of wood procurement costs, which may represent up to
45% of the pulp production cost (Doering, 1997). Other strategies considered
are increased pulp yields, integration of sawmills to secure access to wood
chips, and establishment of SR poplar plantations in areas experiencing wood
supply shortages. Current hardwood chip prices are reasonably low (c.
$80 odMg-1) (Robert, 1999) but reached peak levels only three years
ago, in early 1996 ($140 odMg-1) (International Woodfibre Report,
1997).
The volatility of pulp and paper markets in
addition to the confidential nature of wood procurement costs renders our task
of establishing an average market price for hybrid poplar chips difficult.
Nonetheless, following discussions with industry representatives, a procurement
cost range of $80-$140 odMg-1, with a reference scenario of $100
odMg-1, encompasses most situations, and is used in this study.
Finally, though the present demand for pulp and
paper products is increasing rather slowly, it is anticipated that worldwide
demand may double within the next 20 years. Similarly, demand for alternative
wood chip sources established in close proximity to mills should also increase
in Canada, over the same period. Estimates of growth demand in Canada, and by
region, are beyond the scope of this study.
4.7. Solid Wood and Related Products
Poplar can be used to make excellent quality
particle board, medium density fibre board, and flake board due to its low
density, desirable colour, and suitable gluing characteristics (Geimer and
Crist, 1980). Two drawbacks are its high moisture content and its susceptibility
to rot (Baldwin and Yan, 1968; Balatinez, 1977). Particle board is a
non-structural material that is frequently used for furniture and kitchen
cabinets. U.S. and Canadian consumption of various grades of fibre board is
approximately 7.5 billion square feet (BSF). (RISI Wood Products Review,
1993). Aspen and poplar are viewed as good potential raw materials for
expanding this market. Fibre board can be made from sawdust, shavings, and
wood chips, though the latter is used to a lessor extent because of higher
prices.
Oriented strand board (OSB) is within a class of
composition boards that are made from large flakes or wafers using a phenolic
binder. It is a versatile product, primarily made from round wood, and competes
with exterior plywood in several structural applications such as roof and wall
sheathing, and subflooring (Balatinecz, 1977). Poplar grown in plantations for
the OSB market requires similar production practices and commands the same
price as that for the pulp and paper industry.
Limited research has been directed towards
growing hybrid poplar for longer rotations that would make them suitable for
solid wood products. However, this market has good potential for development as
the supply of high quality timber declines. Lumber demand in North America has
leveled off at approximately 55 to 60 billion board feet (BBF). Poplar,
cottonwood and aspen represented about 4% of Canada’s annual production of 55
million m3 of lumber in 1992 (RISI Wood Products Review,
1993). There has been recent interest in the use of hybrid poplar for
structural lumber. However, it is unlikely that hybrid poplar will become
essential for such a market since it can be used in most other applications of
the forest products industry, and its reputation has been that it is prone to
warping and is relatively weak as construction lumber. Recent forest product
laboratory studies in the U.S. have found hybrid poplar to produce visually
graded material that is similar in properties and characteristics to current
visually graded native aspen and cottonwood (Kretschmann et al., 1999). It has
been found that 65% of the sawn material would fall into the visual grades of
either standard or better or # 2 and better. To avoid excessive degradation as
a result of warping during drying, the material should be dried in the flitch
form. It has been suggested that this might render studding material suitable
for interior walls (Kretschmann et al., 1999). Poplar is becoming a preferred
species for interior trim-work in houses. It is well-received by carpenters as
it works well with power nailguns, requires minimum filling and it stains and
paints smoothly and rapidly (Becker, 1999).
A growing use of poplar as a solid wood product
will most likely be in engineered lumber applications. The growing development
of engineered, high-strength wood products is likely to continue to grow as
solid wood product prices continue to increase and new advances in research and
consumer acceptance of these products grows. Such applications of poplar could
have major impacts on replacing other traditional wood species in solid wood
product markets. The situation may be similar to what has occurred with OSB
substituting for plywood. Long, high-quality logs are becoming scarce and
therefore expensive. However, new technologies are allowing the use of lower
quality wood, such as poplar, to manufacture structural building materials with
sufficient structural strength. These technologies include wood I-beam,
laminated veneer lumber, gluam, parallel strand lumber and parallel chord
trusses. Such industries are relatively new and on the rise. The demand for
long structural material is rising, partly due to a trend for open living
spaces in housing requiring 24 to 36 feet trusses. These building materials
currently have similar or higher prices than solid wood trusses. However,
technological advances as well as a rising price for wood trusses should
increase engineered lumber’s competitive advantage in the near future. Poplar
would be widely used in many applications in this newly-evolving industry.
Balatinecz, J.J. 1977. A
perspective of poplar utilization in Canada-past experience and future
opportunities. 1977. Proceedings of the Annual Meeting; Ontario Ministry
of Natural Resources Forest Information Paper No.102, Pp. 23-1 - 23-6.
Baldwin,
S.H, Yan, M.M. 1968. Utilization of poplar in fibreboard and particle-board.
In: Growth and Utilization of Poplars in Canada, Department for and
Rural Development Dept. Pub. No. 1205.
Becker, B. 1999.
Personal communication.
Council
of Great Lakes Governors. 1995. Wood Pelletization Sourcebook, Great Lakes
Regional Biomass Energy Program. p. 41.
Court, V. 1999. Personal
communication.
Doering, R., F. Bregha,
D. Roberts, S. Thompson and D. Wilson. 1992. Environmental regulations and
the pulp and paper industry: an examination of the Porter strategy.
Working paper prepared for the National Round Table on the Environment and the
Economy
EOMF. 1994. Woodchip
Combustion in Eastern Canada, EOMF Report #7, prepared by Flann Consulting
Services for Resource Efficient Agricultural Production. Ste Anne de Bellevue
Quebec. August 1994. p. 30.
Geimer, R.L., Crist,
J.B. 1980. Structural flakeboard from short-rotation, Intensively cultured
hybrid Poplulus clones. Forest Products Journal 30:6.
Girouard, P., Henning, J.C., Samson, R. 1995.
Economic assessment of SRF and switchgrass plantations for energy production in
central Canada. In: Proceedings of the Canadian Energy Plantation Workshop.
Gananoque, Ontario 2-4 May. Pp 11-16.
Girouard,
P., Samson, R., Zan, C., Mehdi, B. 1998. Economics and carbon offset
potential of biomass fuels. Draft Report. Contract awarded through
Environment Canada’s Environmental Program and funded by the Federal Panel on
Energy Research and Development (PERD). Contract 23341-6-2010/001/SQ.
Grubl, A., R. Hruby, G.
Dell and C. Egger. 1995. Biomass Technologies in Austria: Market study.
Thermie Programme Action BM62. July. p. 86.
International Woodfibre
Report.
1997. Vol. 3. No. 1. January 1997.
Klass, D.L. 1998. Biomass for Renewable Energy,
Fuels, and Chemicals. Academic Press, London.
Kretschmann, D.E., Isebrands, J.G., Stanosz, G,.
Dramm, J.R., Olstad, A., Cole, D., Samsel, J. 1999. Structural lumber properties
of hybrid poplar. United States Department of Agriculture, Forest Service.
Research Paper FPL-RP-573. p. 7.
McCallum, B. 1993. Handbook
for small commercial biomass systems on PEI. Prepared for Energy Mines and
Resources Canada. Charlottetown, Price Edward Island. 30 pp.
Natural Resources Canada - Canadian Forest
Service. 1997. The State of Canada's Forests: learning form history -
1996-1997. Cat. Fo1/1997 E.
RISI Wood Products Review. 1993. North American
Particle Board and Medium Density Fiber Board. Summary Report. Pp 269.
Robert, J. 1999.
Natural Resources Canada. Personal communication.
Rouleau, D. 1994. Biomass
Prospects for future electrical generation plants: A Canadian perspective.
Volume I. Report for the Canadian Electrical Association. Prepared by H.A.
Simons Ltd. CEA Project no. 9230 G 969
Samson, R., Girouard,
P., Mehdi, B., Drisdelle, M., Lapointe, C., Braaten, R., Hall, S. 1999. The
combined use of perennial grass biofuels and gasifier pellet stoves as a
greenhouse gas offset strategy. Prepared for the Combustion and Global
Climate Change Conference, May 26-28, Calgary, Alberta. [In Press].
U.S. Department of Energy. 1992. Solar Thermal and
Biomass Power Division, Office of Solar Energy Conversion. Electricity from
biomass, A development strategy. DOE/CH 10093-152, DE 92010590, April 1992.
Wang, M., Saricks, C., Santini, D. 1999. Effects
of fuel ethanol use on fuel-cycle energy and greenhouse gas emissions.
Argonne National Laboratory. Transportation Technology R&D Center. United
States Department of Energy. Contract W-31-109-Eng-38.
Task 5:
Economics of Carbon Sequestration
5.1. Introduction
One of the main issues
to address when developing policies to mitigate greenhouse gas (GHG) emissions
is the relative cost of each policy option that is required to achieve the
desired objective. Carbon sequestration estimates in forests may vary
substantially depending on biomass growth rates and soil carbon accumulation
levels. The end use of the biomass, after harvest, also plays a key role on the
total carbon emission mitigation effect, from forests as well as the associated
carbon offset cost.
Estimated aboveground,
belowground and potential soil organic carbon accumulation levels in SR hybrid
poplars and willows are reviewed in Task 1. This section integrates the
information in Task 1 with the costs of production and potential market returns
for SR willow and poplar, in order to develop cost estimates of sequestering
carbon in these plantations.
The main limitation of
the analysis is the omission of carbon mitigation arising from the use of the
harvested wood biomass. An analysis of the complete cycle is beyond the scope
of this study.
5.2. Estimated Carbon
Accumulation
5.2.1. Carbon in
Aboveground Standing Tree Biomass
Estimated aboveground
productivity ranges of each tree species for each region (developed in Task 1)
are converted into their carbon productivity equivalent using a carbon to
biomass ratio of 45%. Cumulative carbon accumulation as aboveground biomass is
presented by harvest cycle (Table 5.1 and 5.2).
|
Table 5.1. Aboveground carbon
accumulation per harvest cycle in willow plantations.
|
|
Region
|
Average
Yield
odMg ha-1yr-1
|
Cycle 1
Cumulative Carbon
Accumulation
Mg C ha-1
|
Cycles 2-5
Cumulative Carbon Accumulation
Mg C ha-1
|
|
Yr 1
|
Yr 2
|
Yr 3
|
Yr 4
|
Yr 1
|
Yr 2
|
Yr 3
|
Yr 4
|
|
Atlantic
Provinces
|
5
|
0.34
|
1.80
|
4.05
|
6.30
|
2.25
|
4.50
|
6.75
|
9.00
|
|
10
|
0.68
|
3.60
|
8.10
|
12.60
|
4.50
|
9.00
|
13.50
|
18.00
|
|
Québec
|
7
|
0.47
|
2.52
|
|
8.82
|
3.15
|
6.30
|
9.45
|
12.60
|
|
12
|
0.81
|
4.32
|
9.72
|
15.12
|
5.40
|
10.80
|
16.20
|
21.60
|
|
Ontario
|
7
|
0.47
|
2.52
|
5.67
|
8.82
|
3.15
|
6.30
|
9.45
|
12.60
|
|
12
|
0.81
|
4.32
|
9.72
|
15.12
|
5.40
|
10.80
|
16.20
|
21.60
|
|
Prairie
Provinces
|
2
|
0.14
|
0.72
|
1.62
|
2.52
|
0.90
|
1.80
|
2.70
|
3.60
|
|
6
|
0.41
|
2.16
|
4.86
|
7.56
|
2.70
|
5.40
|
8.10
|
10.80
|
|
British Columbia
|
10
|
0.68
|
3.60
|
8.10
|
12.60
|
4.50
|
9.00
|
13.50
|
18.00
|
|
15
|
1.01
|
5.40
|
12.15
|
18.60
|
6.75
|
13.50
|
20.25
|
27.00
|
Over a 4-year harvest cycle, between 12 -
22 Mg ha-1 of carbon can be accumulated in the standing tree biomass
of SR willow in most regions, with lower values in the Canadian Prairies and up
to 27 Mg ha-1 of carbon in British Columbia. To behave as sinks,
these trees would have to accumulate more carbon than that from the prior
vegetation on the site. However, if forested or abandoned land covered with
thick brush is converted to willow, this projected carbon sink may not occur.
In the case of agricultural or abandoned land covered by herbaceous vegetation,
carbon sequestration may occur at the beginning of year 2 in a harvest cycle.
However, there will be no carbon sequestration occurring following the first harvest
cycle, since the average aboveground carbon will subsequently stabilize at a
new level. Assuming willow is grown in central Canada, on idle land consisting
of herbaceous biomass and light brush estimated to accumulate 7 Mg ha-1
of carbon in its aboveground standing biomass (Zan, 1998), then willow may
initially sequester between 5 and 15 Mg ha-1 of carbon in its
aboveground biomass. A substantial portion of this sink will be removed after
the first harvest, normally after 4 years. Therefore, the main impact of willow
aboveground biomass on GHG mitigation should arise from carbon offsets as a
result of biofuels displacing fossil fuels.
The relatively longer
harvest cycles employed in hybrid poplar production give rise to greater
amounts of carbon being accumulated in poplar aboveground biomass than in
willow. For most regions, carbon accumulation in standing biomass over a
12-year harvest cycle is in the order of 12-34 Mg ha-1. Longer
harvest cycles in hybrid poplar are apt to result in carbon sinks of greater
duration than those of willow plantations, this may have important policy
implications. If SR poplar is established in central Canada on an idle field
consisting mainly of herbaceous vegetation and light brush representing 7 Mg ha-1
of carbon in the aboveground biomass, between 2 and 27 Mg ha-1 of
carbon could be sequestered up to year 12 of the first poplar harvest cycle.
Beyond this period, this substantial carbon sink will be removed unless the
carbon harvested is retained in long-lasting materials such as those used for
construction, or if the biomass is used for biofuel production. This issue is
just beginning to be addressed in a systematic way (e.g. Marland et al.,
1996).
5.2.2. Carbon in
Belowground Biomass
Belowground biomass carbon
accumulation within hybrid poplar and willow plantations is largely dependent
upon root mass and level of living organisms. Carbon accumulation in roots and
stumps of poplar and willow is presented in Task 1. Using these values, an
average carbon stock is estimated for both tree species (Table 5.3). Over the
20-year life span of the plantation, willow is estimated to maintain an average
belowground carbon stock of 4.03 Mg ha-1. Similarly, over the
12-year life span of a poplar plantation, an average of 4.39 Mg ha-1
of carbon will be maintained as a belowground carbon stock. These estimates are
based on root biomass levels eventually attaining a steady-state, a rather
simplistic assumption that is necessary at present given the poor understanding
of root production dynamics in SR tree systems.
|
Table 5.3. Estimated
belowground biomass and corresponding carbon content.
|
|
|
Biomass
|
Carbon
|
Biomass
|
Carbon
|
Biomass
|
Carbon
|
|
|
odMg ha-1
|
Mg ha-1
|
odMg ha-1
|
Mg ha-1
|
odMg ha-1
|
Mg ha-1
|
|
Willow
|
Year 1-3
|
Year 4-20
|
Weighted Average
|
|
|
3
|
1.35
|
10
|
4.5
|
8.95
|
4.03
|
|
Poplar
|
Year 1-3
|
Year 4-12
|
Weighted Average
|
|
|
3
|
1.35
|
12
|
5.4
|
9.75
|
4.39
|
To constitute a carbon
sink, belowground biomass carbon stock levels must be greater than levels
present on the site prior to the establishment of the SRF crop. Since
belowground carbon levels are relatively low (in the 4 Mg ha-1
range), it is assumed that the belowground biomass carbon stock will not be
considered as a carbon sink for the remainder of Task 5. Therefore, carbon
sequestration resulting from root production is assumed to be incorporated
within the soil organic carbon pool.
5.2.3. Soil Organic
Carbon Pool
The discussion in Task 1 focussing on
potential increases in soil organic carbon levels from the adoption of hybrid
poplar and willow plantations emphasizes the need to obtain more soil data in
SRF systems, especially under varying field conditions and crop management
regimes. The possibility of soil organic carbon losses in the years following
the establishment of SR trees has also been highlighted. For the analysis
presented in this section, three possible scenarios are investigated: (1) no
soil organic carbon accumulation, (2) a carbon accretion rate of 1.5 Mg ha-1yr-1
and (3) a carbon accretion rate of 3.0 Mg ha-1yr-1. These
totals are assumed to be averages over the life span of the plantations,
whereby carbon may be lost in some years and replaced in others. Table 5.4
presents the absolute change in soil organic carbon for hybrid poplar and
willow for each scenario.
|
Table 5.4. Change in soil
carbon stock for different rates of soil organic carbon (SOC) accumulation.
|
|
|
Hybrid Poplar
Change in SOC Level over 12
Years
Mg ha-1
|
Willow
Change in SOC Level over 20
Years
Mg ha-1
|
|
Annual Accumulation
|
0
|
1.5
|
3.0
|
0
|
1.5
|
3.0
|
|
Total Accumulation
|
0
|
18
|
36
|
0
|
30
|
60
|
5.3.
Cost Estimates of Carbon Sequestration
Estimating the cost of
sequestering carbon in hybrid poplar and willow plantations is performed using
a number of simplifying assumptions, and aims at providing order of magnitudes
of the potential costs. More detailed studies are required to develop specific
estimates.
5.3.1. Cost of
Sequestering Soil Organic Carbon
5.3.1.1 Scenario 1: Entire
Plantation Life Span
An evaluation of the economics of carbon
sequestration involves two main features: the amount of carbon sequestered and
the costs involved in performing the operation. Scenario 1 uses the estimated
cost of growing SR trees along with the soil organic carbon accumulation
scenarios presented in Table 5.4, to develop the cost per Mg of CO2
sequestered. Short rotation trees were assumed to be planted in the spring of
2001, with an expected lifespan of 12 and 20 years for hybrid poplar and
willow, respectively.
Hybrid poplar is harvested in year 2012 while willow is harvested every four
years beginning in year 2004 and ending in year 2020.
The annual cost per ha associated with
growing, harvesting, and transporting chips to conversion plants are estimated
in Task 3. The present value of these costs, using a 10% discount rate, is
estimated for each respective plantation lifespan, and the results are divided
by the cumulative soil organic carbon sequestered over the corresponding
period. Carbon values are not discounted in this analysis, and all costs are
expressed in 1995 dollars, which is the base year used in the BIOCOST
softwares. Task 3 estimates annual costs of production on both a variable and
full economic cost basis. In order to reduce the number of simulations to be
performed in Task 5, the cost of production is averaged over the full economic
cost and variable cost. For specific values, refer to Appendix 2. Estimated
costs of carbon sequestered for Scenario 1 are summarized in Table 5.5. All
values are expressed in Mg of CO2.
|
Table 5.5. Scenario 1 – Estimated cost of
soil organic carbon sequestration over SR tree plantation lifespan.
|
|
Region
|
Expected Annual Harvestable Biomass Yield
Range by Region
(odMg ha-1yr-1)
|
SOC Accumulation Rate
|
|
1.5 Mg ha-1yr-1
|
3.0 Mg ha-1yr-1
|
|
Harvestable Biomass Yield in a Region
|
|
Minimum
|
Maximum
|
Minimum
|
Maximum
|
|
Estimated
Discounted Cost of Carbon Sequestered
($ Mg-1 CO2)
|
|
Hybrid Poplars – 12 year lifespan
|
|
Atlantic
Provinces
|
2
|
6
|
33
|
42
|
17
|
21
|
|
Québec
|
2.5
|
7
|
34
|
43
|
17
|
22
|
|
Ontario
|
2.5
|
7
|
34
|
43
|
17
|
22
|
|
Prairie
Provinces
|
1
|
5
|
31
|
40
|
16
|
20
|
|
British
Columbia
|
9
|
12
|
49
|
54
|
24
|
27
|
|
SR Willows – 20 year lifespan
|
|
Atlantic
Provinces
|
5
|
10
|
35
|
42
|
18
|
21
|
|
Québec
|
7
|
12
|
38
|
45
|
19
|
22
|
|
Ontario
|
7
|
12
|
38
|
45
|
19
|
22
|
|
Prairie
Provinces
|
2
|
6
|
32
|
37
|
16
|
18
|
|
British
Columbia
|
10
|
15
|
42
|
49
|
21
|
24
|
|
|
|
|
|
|
|
|
The cost associated with sequestering
carbon in soil is similar for both crops. For example, at a soil organic carbon
average annual accumulation rate of 1.5 Mg, hybrid poplar and willow may
sequester carbon for $31-$54 Mg-1 CO2 and $32-$49 Mg-1
CO2, respectively, in Canada. A doubling of soil organic carbon
accumulation rate will reduce the cost of carbon sequestered by half (i.e.
16-$27 Mg-1 CO2 for hybrid poplar; $16-$24 Mg-1
CO2 for willow). The main limitation to the approach employed in
Scenario 1 is that cost of CO2 sequestered increases with increases
in harvestable yield as a result of higher harvest and transportation costs per
hectare.
5.3.1.2 Scenario 2: Commitment Period
2008-2012 Only
The first commitment period under the
Kyoto Protocol runs from the year 2008 to 2012. In Scenario 2, the present
value of costs incurred over the lifespan of SR hybrid poplar and willow
plantations are associated to the soil organic carbon sequestered over the
period 2008-2012 to determine the cost of carbon sequestered. In other words, Scenario
2 assumes that the present value of cost is attributed solely to carbon
sequestered over the first commitment period, as opposed to over the entire
plantations lifespan (i.e. Scenario 1). The results are presented in Table
5.6.
|
Table 5.6. Scenario 2 – Estimated cost
of soil organic carbon sequestration in SR tree plantations over 2008-2012.
|
|
Region
|
Expected Annual Harvestable Biomass Yield
Range by Region
(od Mg ha-1yr-1)
|
SOC Accumulation Rate
|
|
1.5 Mg ha-1yr-1
|
3.0 Mg ha-1yr-1
|
|
Harvestable Biomass Yield in a Region
|
|
Minimum
|
Maximum
|
Minimum
|
Maximum
|
|
Estimated Discounted Cost of Carbon
Sequestered
($ Mg-1 CO2)
|
|
Hybrid Poplars – 12 year lifespan
|
|
Atlantic
Provinces
|
2
|
6
|
80
|
100
|
40
|
50
|
|
Quebec
|
2.5
|
7
|
82
|
104
|
41
|
52
|
|
Ontario
|
2.5
|
7
|
82
|
104
|
41
|
52
|
|
Prairie
Provinces
|
1
|
5
|
75
|
96
|
37
|
48
|
|
British
Columbia
|
9
|
12
|
116
|
131
|
58
|
65
|
|
SR Willows – 20 year lifespan
|
|
Atlantic
Provinces
|
5
|
10
|
142
|
168
|
71
|
84
|
|
Quebec
|
7
|
12
|
152
|
179
|
76
|
89
|
|
Ontario
|
7
|
12
|
152
|
179
|
76
|
89
|
|
Prairie
Provinces
|
2
|
6
|
126
|
147
|
63
|
74
|
|
British
Columbia
|
10
|
15
|
168
|
194
|
64
|
97
|
Under Scenario 2, the cost associated
with soil organic carbon sequestration is much higher than in Scenario 1. For
instance, at a soil organic carbon accumulation rate of 1.5 Mg ha-1yr-1,
carbon sequestration in hybrid poplar and willow will cost between $75-131 Mg-1
CO2 and $126-$194 Mg-1 CO2, respectively.
5.3.2. Cost of
Sequestering Carbon in Soil and Aboveground Biomass
5.3.2.1 Scenario 3: Entire
Plantation Life Span
The growing of hybrid
poplar and willow under short harvest cycles can lead to increases in average
annual biomass production compared with natural stands, and can provide faster
returns on investment. As discussed previously, however, shorter harvest cycles
experienced in these systems can limit the effectiveness of aboveground
standing biomass to develop carbon sinks. In Scenario 3, the estimated
aboveground carbon sequestration over production from an abandoned field (i.e.
7.0 Mg C ha-1 developed in section 5.2.1), is added to the soil
organic carbon accumulation scenarios used in Table 5.5. The cost associated
with sequestering carbon over the entire lifespan of each respective tree
species is then computed using the same present value of costs as in Scenarios
1 and 2. Results are presented in Table 5.7.
|
Table 5.7. Scenario 3 – Estimated cost
of sequestering soil organic carbon and carbon in standing tree biomass over
SR tree plantation lifespan.
|
|
Region
|
Expected Annual Harvestable Biomass Yield
Range by Region
(od Mg ha-1yr-1)
|
SOC Accumulation Rate
|
|
1.5 Mg ha-1yr-1
|
3.0 Mg ha-1yr-1
|
|
Harvestable Biomass Yield in a Region
|
|
Minimum
|
Maximum
|
Minimum
|
Maximum
|
|
Estimated Discounted Cost of Carbon
Sequestered
($ Mg-1 CO2)
|
|
Hybrid Poplars – 12 year lifespan
|
|
Atlantic
Provinces
|
2
|
6
|
29
|
19
|
15
|
13
|
|
Quebec
|
2.5
|
7
|
27
|
17
|
15
|
12
|
|
Ontario
|
2.5
|
7
|
27
|
17
|
15
|
12
|
|
Prairie
Provinces
|
1
|
5
|
35
|
20
|
17
|
13
|
|
British
Columbia
|
9
|
12
|
16
|
14
|
12
|
11
|
|
SR Willows – 20 year lifespan
|
|
Atlantic
Provinces
|
5
|
10
|
33
|
31
|
17
|
18
|
|
Quebec
|
7
|
12
|
32
|
30
|
17
|
18
|
|
Ontario
|
7
|
12
|
32
|
30
|
17
|
18
|
|
Prairie
Provinces
|
2
|
6
|
36
|
33
|
17
|
17
|
|
British
Columbia
|
10
|
15
|
31
|
29
|
18
|
18
|
When carbon sequestered
in the aboveground biomass is included with the carbon sequestered in the soil,
costs associated with carbon sequestration are be reduced to $14-$35 Mg-1
CO2 and $26-$36 Mg-1 CO2 in hybrid poplar and
willow, respectively, at a soil organic carbon accretion rate of 1.5 Mg ha-1yr-1.
Compared with values developed in Scenario 1, these represent an average
reduction in cost of 42% for SR hybrid poplar and a 20% in SR willow.
5.3.2.2 Scenario 4:
Commitment Period 2008-2012 Only
Similarly to Scenario 2,
Scenario 4 investigates the cost of sequestering carbon over the period of
2008-2012, but with the inclusion of carbon sequestered in aboveground standing
biomass. The present costs are similar to those employed in the previous
scenarios. For hybrid poplar, the cumulative aboveground biomass carbon stock
at the end of 2007 is, in most cases, approximately equal to, or superior to,
the benchmark value used to compute aboveground carbon sequestration in this
study (i.e. 7.0 Mg ha-1 of carbon). Therefore, aboveground carbon
accumulated in hybrid poplar from 2008-2012 is assumed to act as a carbon sink.
Short rotation willow established in 2001 will complete their second harvest
cycle by the end of 2008. By then, average aboveground carbon levels will have
stabilized to a new level, indicating no further carbon sink compared with the
previous land-use. It is therefore assumed that no carbon sequestration in
willow aboveground biomass will occur during the period of 2008-2012.
|
Table 5.8. Scenario 4 – Estimated cost of
soil organic carbon sequestration in SR tree plantations over 2008-2012.
|
|
Region
|
Expected Annual Harvestable Biomass Yield
Range by Region
(odMg ha-1yr-1)
|
SOC Accumulation Rate
|
|
1.5 Mg ha-1yr-1
|
3.0 Mg ha-1yr-1
|
|
Harvestable Biomass Yield in a Region
|
|
Minimum
|
Maximum
|
Minimum
|
Maximum
|
|
Estimated Discounted Cost of Carbon
Sequestered
($ Mg-1 CO2)
|
|
Hybrid Poplars – 12 year lifespan
|
|
Atlantic
Provinces
|
2
|
6
|
50
|
36
|
31
|
26
|
|
Quebec
|
2.5
|
7
|
47
|
34
|
30
|
25
|
|
Ontario
|
2.5
|
7
|
47
|
34
|
30
|
25
|
|
Prairie
Provinces
|
1
|
5
|
57
|
38
|
32
|
27
|
|
British
Columbia
|
9
|
12
|
31
|
28
|
25
|
23
|
|
SR Willows – 20 year lifespan
|
|
Atlantic
Provinces
|
5
|
10
|
---
|
---
|
---
|
---
|
|
Quebec
|
7
|
12
|
---
|
---
|
---
|
---
|
|
Ontario
|
7
|
12
|
---
|
---
|
---
|
---
|
|
Prairie Provinces
|
2
|
6
|
---
|
---
|
---
|
---
|
|
British
Columbia
|
10
|
15
|
---
|
---
|
---
|
---
|
|
|
|
|
|
|
|
|
Results form Scenario 4
indicate that the cost of carbon sequestration in SR hybrid poplar from the
period of 2008-2012 would be $28-$57 Mg-1 CO2, for a soil
organic accretion rate of 1.5 Mg
C ha-1yr-1. This represents an average cost reduction of
approximately 55% compared to values estimated in Scenario 2.
5.3.3 Scenario 5:
Cost of Carbon Sequestration Including Market Revenues for the Biomass Produced
Scenarios 1 to 4 have estimated the cost
of carbon sequestration based on the costs of growing hybrid poplar and willow.
Provided there is a profitable market for the biomass produced from each of
these crops, carbon sequestration could occur concomitantly to the commercial
activities, with no real cost associated with carbon sequestration. In the
event that private landowners do not engage in SR tree activities as a result
of a lack of profitability, monetary credits for carbon sequestered could
provide the necessary incentive to landowners. Scenario 5 investigates the
effect of two different market prices ($50 and $100 odMg-1) for the
biomass produced on the net present value (NPV) of SR tree plantations. In the
event that the NPV is negative, incentives are required to engage landowners
into SR tree cropping. The value of the incentives required, provided through
credits for carbon sequestration, is estimated by dividing the value of the NPV
by the cumulative carbon sequestered. In this scenario, carbon sequestration is
based on a soil organic carbon accretion rate of 1.5 Mg ha-1yr-1
over the lifespan of hybrid poplar and willow plantations.
|
Table 5.9: Scenario 5 – Effect of Biomass
Market Price on the NPV of SR Tree Species Expressed per Mg of Carbon
Sequestered
|
|
Region
|
Expected Annual Harvestable Biomass Yield
Range by Region
(od Mg ha-1yr-1)
|
Biomass Market Price
|
|
$50 odMg-1
|
$100 odMg-1
|
|
Harvestable Biomass Yield in a Region
|
|
Minimum
|
Maximum
|
Minimum
|
Maximum
|
|
Estimated
NPV per Mg Carbon Sequestered
($ Mg-1 CO2)
|
|
Hybrid Poplars – 12 year lifespan
|
|
Atlantic
Provinces
|
2
|
6
|
-28
|
-26
|
-23
|
-10
|
|
Quebec
|
2.5
|
7
|
-28
|
-25
|
-21
|
-7
|
|
Ontario
|
2.5
|
7
|
-28
|
-25
|
-21
|
-7
|
|
Prairie
Provinces
|
1
|
5
|
-28
|
-27
|
-26
|
-14
|
|
British
Columbia
|
9
|
12
|
-25
|
-23
|
-2
|
8
|
|
SR Willows – 20 year lifespan
|
|
Atlantic
Provinces
|
5
|
10
|
-21
|
-12
|
-6
|
17
|
|
Quebec
|
7
|
12
|
-17
|
-9
|
3
|
26
|
|
Ontario
|
7
|
12
|
-17
|
-9
|
3
|
26
|
|
Prairie
Provinces
|
2
|
6
|
-26
|
-19
|
-20
|
-1
|
|
British
Columbia
|
10
|
15
|
-12
|
-4
|
17
|
40
|
Note: SOC
accumulation rate = 1.5 Mg C ha-1yr-1
Negative values presented in Table 5.9
indicate that the present value of revenues generated over the life span of the
plantation is not sufficient to cover the present value of the flow of
expenses. If SR tree biomass is selling at $50 odMg-1 throughout the
lifespan of the plantation, soil organic carbon sequestered in hybrid poplar
must sell for $23-$28 Mg-1 CO2 to return the NPV to zero.
Similarly, soil organic carbon under willow plantations will have to sell for
$4-$26 Mg-1 CO2. The short term and more regular
revenues in SR willow production improves the NPV of SR willow compared with SR
hybrid poplar. If SR tree biomass is selling for $100 odMg-1, carbon
may be sequestered in hybrid poplar for $2-$26 Mg-1 CO2,
and at no cost in most cases for willow. Unfortunately, a selling price of $100
odMg-1 for willow chips does not appear to be realistic, as the crop
is currently targeted mostly for energy applications.
5.4. Conclusion
The main objective pursued in Task 5 was
to develop estimates of the cost associated with carbon sequestration in hybrid
poplar and willow plantations. Most scenarios including a soil organic carbon
accretion rate of 1.5 Mg C ha-1yr-1 led to estimates
between $14 and $54 Mg-1 of CO2 sequestered for hybrid
poplar and $4 to $49 Mg-1 CO2 for willow.
Literature Cited
Marland, F., Schlamadinger,
Leiby, P. 1996. Forest/Biomass Based Mitigation Strategies: Does the Timing of
Carbon Reductions Matter? In Press
Samson, R., Girouard, P., Omielan, J., Chen, Y.,
Quinn, J. 1995. Technology evaluation and development of SRF for energy
production. Final Report. Report completed under the Federal Panel on
Energy Research and Development (PERD) for Natural Resources Canada and
Agriculture Canada. Contract 23440-2-94933/01SQ.
Zan, C. 1998. Carbon
storage in two biomass energy plantations in southwestern Québec. M.Sc.
Thesis. McGill University. Montréal, Canada. 109 pp.
Task 6: Potential Land Base for
Short-Rotation Tree Production in Canada
Potential markets suited for hybrid poplar and willow are
briefly reviewed in Task 4 by region, and potential regions best suited for
afforestation programs are discussed in Task 7. This section provides
information on potential land base availability for afforestation programs.
Although the precise definition of afforestation within
the Kyoto Protocol is currently being reviewed, afforestation usually
encompasses the establishment of forest vegetation on land that has not
previously been forested or has not been forested in a long time (Sedjo et al.,
1998). Therefore, within the context of this definition, afforestation programs
that qualify under the Kyoto Protocol make particular use of agricultural
land.
Soil types most suitable for poplar and willow production
generally exhibit moderate to high levels of soil fertility and sufficient soil
moisture during the growing season to sustain high tree productivity thus
resulting in positive economics. Also, tile drained land in British Columbia
and eastern Canada will not be planted to poplars or willows because of
problems with the tree crops plugging drains. In the Canadian Land Inventory
(CLI) classification system of agricultural land suitability, mineral soils are
grouped into seven classes according to their potential to sustain agricultural
production (Environment Canada, 1976). Classes 1 to 3 are considered
capable of sustained annual production of common agricultural crops and
therefore usually not considered for SR tree production (e.g. Threshold
Technologies Company, 1995; Wamsley and Standish, 1996). Conversely, when
land is classified as class 7, it is unsuitable for agricultural use. Thus,
afforestation programs are typically developed on soils having capability
classes 4 to 6 as described below:
·
Class 4: land having severe limitations restricting crop
range or requiring special conservation practices;
·
Class 5: land having very severe limitations restricting
their capability to produce perennial forage crops;
·
Class 6: land capable of producing only perennial forage
crops.
Given the soil fertility requirements of hybrid
poplar and willow, economically viable production will mostly occur on soil
classes 4 and 5. Experience acquired with poplar production in eastern Ontario
suggests that the use of “poor” marginal land is not economically viable.
Rather, the rule of thumb now appears to be the use of so-called “good”
marginal lands, which probably encompasses land classes 4 and 5 that have
sufficient moisture levels and adequate drainage. In a preliminary feasibility
study evaluating agroforestry opportunities in Manitoba, Threshold
Technologies Company (1995) also did not consider soils having soil
capability classes 1-3 for hybrid poplar production, and identified classes 4
and 5 as most promising. The land base within these two soil classes was
further evaluated to estimate the area that would have been graded higher for
agricultural crop production were it not for the presence of excessive soil
moisture at some time during the growing season. Although some of this land
may be too wet for poplar or aspen production, much of it could provide an
environment for near-optimal growth of poplar according to Threshold
Technologies Company (1995).
It is beyond the scope of this study to develop a soil
suitability matrix for poplar and willow production and treat this information
with existing GIS technology in order to estimate agricultural land rated as
good, fair, and poor for these production systems as well as those areas
potentially available given current land use patterns. The approach followed in
this study is rather to focus the analysis on areas across Canada rated within
soil classes 4 and 5 and develop potential scenarios for their suitability
within SR tree production systems.
Land base availability for energy crop production in
Canada was estimated by Seecharan (1984) in a working paper prepared for Agriculture
Canada. The study was performed for the production of corn, wheat, soybean,
kochia and jerusalem artichoke grown for energy production on marginal land,
that is, land in soil capability classes 4 to 6. Land base availability
estimates for classes 4 and 5 computed in this study are presented in Table
6.1.
|
Table 6.1. Total and
estimated usable area of class 4 and 5 agricultural land for energy crop
production by province and CLI class.
|
|
|
Land Class
|
|
|
|
4
|
5
|
Total of Class 4 &
5 Lands
|
|
Province
|
Total
|
Usable for energy
Cropsa,b
|
Total
|
Usable for energy
Cropsa,b
|
Total
|
Usable for energy
Cropsa,b
|
|
British
Columbia
|
1,701,678
|
n/a
|
6,671,675
|
n/a
|
8,373,353
|
n/a
|
|
Alberta
|
9,279,579
|
3,478,578
|
11,093,057
|
4,208,315
|
20,372,636
|
7,686,893
|
|
Saskatchewan
|
3,893,109
|
1,317,136
|
8,736,287
|
4,147,384
|
12,629,396
|
5,464,520
|
|
Manitoba
|
2,394,118
|
383,232
|
2,323,786
|
403,666
|
4,717,904
|
786,898
|
|
Ontario
|
2,624,648
|
495,263
|
1,915,301
|
310,666
|
4,539,949
|
805,929
|
|
Québec
|
2,580,503
|
1,031,444
|
1,658,600
|
517,707
|
4,239,103
|
1,549,151
|
|
New
Brunswick
|
2,032,089
|
345,558
|
1,700,253
|
158,965
|
3,732,342
|
504,523
|
|
Nova
Scotia
|
424,410
|
115,756
|
82,215
|
29,908
|
506,625
|
145,664
|
|
Prince
Edward Island
|
49,776
|
17,321
|
76,064
|
19,943
|
125,840
|
37,264
|
|
Newfoundlandc
|
16,613
|
n/a
|
91,517
|
n/a
|
108,130
|
n/a
|
|
TOTAL
|
24,996,520
|
7,184,288
|
34,348,755
|
9,795,964
|
59,345,275
|
16,980,252
|
Adapted from Seecharan (1984)
n/a not available
a consists mainly of
non-productive woodland, improved pasture, rough grazing and rangeland
b energy crops included
corn, wheat, soybean, kochia and jerusalem artichoke in the study
c includes areas of
Newfoundland within a 161 km radius of St. John.
Canada accounts for 25 and 34 million ha of land in
classes 4 and 5, respectively (Table 6.1). In further processing these data to
restrict the area of each soil class to land use consisting mainly of
non-productive woodland, improved pasture, rough grazing and rangeland,
Seecharan (1984) estimated that 7.1 million ha of soil capability class 4 and
9.8 million hectares of soil capability class 5 could be available for energy
crop production, that is nearly 17 million ha. The subset of this area not only
capable of supporting economically viable poplar and willow plantations but
actually available, still remains to be defined. However, assuming that 25% to
75% could be potentially used, then 4.25 to 12.75 million ha of land could be
afforested in Canada. However much of this marginal land could also be used for
production of perennial grasses for fibre and energy markets. Given that
farmers tend to prefer the production of herbaceous biomass crops over tree
plantations (Campbell et al. 1986), difficulties may be encountered when
convincing farmers to tie up their lands for extended periods, given that
alternative farming systems may be available.
Data for British Columbia were not available
from Seecharan’s (1984) study, however a recent study estimated that 1.5 to 4
million ha of the Agricultural Land Reserve could be available for forestry
uses. Based on Statistics Canada census data, approximately 940,000 ha of private
farmland is potentially available as well (Nawitka Renewable Resource
Consultants Ltd, 1996). Nonetheless, the area actually suitable for hybrid
poplar is likely much smaller, only an additional 10,000 ha was foreseen to be
available to be planted in the lower mainland of British Columbia (See Task 7).
In their preliminary feasibility study on
agroforestry opportunities in Manitoba, Threshold Technologies Company
(1995) indicated that as much as 0.4 million ha of class 4 land and another 0.6
million ha of class 5 land may be suitable for hybrid poplar, slightly more
than what is estimated in Table 6.1.
In terms of land base availability, Alberta and
Saskatchewan would be the most promising areas to establish a substantial
afforestation program. Nonetheless, as discussed in Task 1 and later in Task 7,
the climatic conditions and soil moisture limitations prevailing in these
regions are major concerns. Based on preliminary results from Threshold
Technologies Company (1995), Manitoba could prove to be a promising region,
especially since current wood resources are limiting the future expansion of
fibre industries in the region.
Land base availability for afforestation in
eastern located programs appears, at first glance, to be more limited, but more
favourable growing conditions in the region will improve productivity and very
likely the overall cost competitiveness of the plantations. The main deterrent
to the economics of tree plantations in Québec and Ontario may be the higher
opportunity cost of land targeted for afforestation than in the Prairie and
Atlantic regions. Provided afforestation occurs on idle land, there obviously
will be no effect, but if afforestation migrates towards higher value land, the
more intensive nature of agricultural cropping in the region (higher net
returns per ha) may dictate higher opportunity cost to access the
land.
In summary, land appears to be available in
Canada to develop an afforestation program using short rotation hybrid poplars
and willows, possibly in the order of 4.25 to 12.75 million ha. Some of this
land base will likely be more suitable for other types of energy crops, such as
perennial grasses. These crops are better adapted to regions with low rainfall,
soils of low water holding capacity and have a lower cost of production per od
Mg of biomass produced (Girouard et al., 1995). Given that the main carbon
offset benefits derived from SR tree crops are most likely to be from the
displacement of fossil fuel products, it may be warranted to estimate the
carbon offset cost incurred with these alternative crops concomitantly to
evaluating the benefits of afforestation.
Literature Cited
Environment Canada. 1976. Canada Land
Inventory: land capability for agriculture- Preliminary Report. Lands
Directorate. p. 27.
Girouard, P., Henning,
J.C., Samson, R. 1995. Economic assessment of SRF and switchgrass plantations
for energy production in central Canada. In: Proceedings of the Canadian
Energy Plantation Workshop. Gananoque, Ontario 2-4 May. Pp 11-16.
Nawitka Renewable
Resource Consultants Ltd., 1996. Expanding Productive Forest Cover in BC,
Report prepared for Forest Renewal BC. April 30. p. 20.
Sedjo, R., Sohngen, B.,
and Jacgger, P. 1998. Carbon Sinks in the Post-Kyoto World: Part 1. Resources
for the Future (RFF). Washington, DC. USA. p. 6.
Seecharan, R. 1984. Determination of the land
resource base, biomass production and estimated costs of production for energy
crops. Input and Technology Analysis Division. Energy and Technology
Assessment Section. Development Policy Directorate. Agriculture Canada.
Walmsley, M.E., and Standish, J. 1996. Expansion
of Productive Forest Cover on Selected B.C. Lands: A Review of Existing Data on
under-utilized lands with forest growth potential. Westland Resource
Group. Prepared for Nawitka Renewable Resource Consultants Ltd., as a
component of the report Expanding Productive Forest Cover in BC,
prepared for Forest Renewal BC.
7.1. Introduction
Experience in growing SR trees within
afforestation programs implemented in northern regions of North America has
almost exclusively been limited to hybrid poplar. The work demonstrates three
common features to be singled out as key components to a successful program:
1. Perceived Need: A strong demand for
fibre in the area is necessary to encourage plantings, and to have strong
market prices. Areas with existing wood deficits or forecast shortages are the
best target areas.
2. Requisite Talent: It is of primary
importance to have a certain amount of experienced scientists and
silviculturalists in the region, specializing in fast growing trees and who
have developed adept germplasm. Ideally, a fast growing tree breeding program
should be in place to provide regionally adapted material for the program.
3. Suitable Land Base: A large land base of
underutilized agricultural land that is capable of achieving productive growth
rates is ideal.
The Canadian and U.S. experiences with fast
growing trees are relatively similar. In both countries, industry-led programs
have been essential to scaling up plantations.
The largest afforestation program using fast
growing poplar or willow occurring to date is the hybrid poplar program of the
Pacific Northwest. In 1996, there were 26,900 ha of hybrid poplar in this
region (Wright and Tuskan, 1997). Tree plantation locations are approximately
equally split between the fertigated east, and the non-irrigated west sites of
the Cascade Mountains. Operational field yields have been reported by
contractors of the U.S. Department of Energy to be between 11 and 22 odMg ha-1yr-1
(Wright and Tuskan, 1997) and managed on 6-9 year rotations.
The program has been successful due to various factors.
The region has relatively high fibre prices since much of the fibre is imported
into pulp mills within the region (in part due to new environmental
restrictions on logging). Moreover, the west side of the mountain range
receives abundant rainfall, furthermore, due to a favourable growing season,
rotation cycles are relatively rapid compared with other regions. In addition,
a research and development consortium was established between industry and
university scientists to develop improved plant materials. Breeding programs
are now led by individual companies. Drawbacks to the plantation program in the
Pacific Northwest are the limited land base and high demand and costs of water
for the irrigation on the east side. The program has achieved much success largely
due to a strong emphasis placed on tree improvement through germplasm
collection and evaluation, as well as plant breeding. Approximately 20-30
operational clones exist in the region, which is 3 to 4 times higher than the
average for other regions.
7.2.2 The North Central Region
Minnesota, the most recent region with larger
scale hybrid poplar plantings in the U.S., is the state with highest poplar
research activity. The main reason for this has been the growing realization of
an impending fibre crisis in the region as a result of the ongoing depletion of
hardwood resources by the oriented strand board and pulp and paper industries.
Historically, Minnesota has had a strong hybrid
poplar research effort with thirty years of research on poplar production,
physiology, and breeding, performed by the University of Minnesota and the U.S.
Forest Service. The main reason being the strong support it has received from
the U.S. Department of Energy. The scale up program consisting of two projects
was established primarily in the mid-1990. One project, funded by the U.S.
Department of Energy, involved a scale up of an 800 ha area of Alexandria,
Minnesota. The second project was the Oklee Tree Project established in
Northwestern Minnesota. The latter project provides a good example of how to
initiate tree planting in a region. The project involved a cooperative effort
between the Agricultural Utilization Research Institute (AURI), University of
Minnesota-Crookston, Natural Resources Research Institute (NRRI), Minnesota
Power (MP) and local, state, as well as federal agencies. The goal was to plant
1,200 ha of poplars within a 50-km radius of Oklee, Minnesota, initiated in the
spring of 1995. The project determined the economic feasibility of planting
hybrid poplars as an alternative cash crop, and to provide an opportunity for
the future development of a biomass energy facility. Trees that were planted on
Conservation Reserve Program (CRP) land were eligible to receive: 5-year
contract extensions, cost sharing for establishment from an Agricultural
Stabilization and Conservation Service (ASCS), US$ 85 acre-1 (CAN$
315 ha-1) for establishment from a grant from the Legislative
Commission of Minnesota Resources to AURI, and 30-year contracts from MP (which
include guaranteed purchase contracts for wood and yearly payments to growers).
Planting areas were selected based on number of available acres, suitable soil
types and growing conditions, proximity of wood markets, high pressure gas and
electric transmission lines, cooperation of local, state and federal agencies,
and willingness of growers to consider hybrid poplars as an alternative crop.
The program was initiated by letters outlining the plan, sent to all CRP
contract holders in the area, and by conducting 3 local information meetings.
Interested growers filled out and returned a form permitting access to their
sites for measurements of pH, organic matter, slope, drainage, water holding
capacity and depth to water table. Each site was rated for suitability of hybrid
poplar growth, plantation size, and distance from Oklee. Growers determined
when to plant poplars, grown at densities of 1,200-1,700 trees ha-1 and
on rotations of 10-15 years, using similar cultural practices as in other
regions.
To date, some shortcomings experienced include
the cottonwood leaf beetle and septoria canker. Breeding efforts have been
focussed on developing canker-resistant clones. No solution has yet been
developed for the cottonwood leaf beetle. It became a nuisance to the majority
of plantings in Minnesota, which were consequently sprayed with insecticide in
1998. Some plantings were sprayed on two occasions.
Commercial interest from the fibre industries
now appears to be the driving force of the Minnesota poplar program. There are
aspen wood deficit forecasts for the region within the next 20 years and the
forest resource in Minnesota has reached its maximum allowable annual cut. The
paper company Champion has been the industry leader, having announced
plans to purchase or lease 6,900 ha for hybrid poplar plantings in the vicinity
of its Sartell paper mill. Other wood fibre companies in the research
and development phase with poplars are Potlatch, Boise Cascade
and Blandon. Along with Champion, they have formed a research
cooperative with the University of Minnesota, the U.S. Forest Service and the
U.S. Department of Energy.
A new potential poplar user is the power
generation industry. An announcement was made in late 1998 that Northern
State Power would purchase power for a 25 MW (mega watt) facility to run on
closed-loop biomass plantings of hybrid poplar. Several phases will be involved
in the project, of which the first phase involves planting hybrid poplar. A
Minnesota company, known as Energy Performance Systems, will build a
whole tree burner to use the plantings. This will require an additional 10,000
ha of hybrid poplar plantings in the region. However, there is concern that the
market value for wood for the fibre market will exceed its potential value for
energy, and that the hybrid poplar plantings may not be used in an electrical
energy end-use market.
7.2.3. Northeast
The main wood species currently undergoing scale
up is hybrid willow managed in the form of the Swedish-style twin row system.
High-density plantings (15,000 cph) are being managed on a 3-4 year coppice
management system. The program is led by the State University of New York in a
cooperative effort with U.S. Department of Energy, Electric Power Research
Institute, several regional power companies, the cooperative extension agency,
as well as other collaborators. The project planted 40 ha of willows in 1998
with four operational clones. Plans for another 80 ha and 125 ha in 1999 and
2000, respectively, are in progress. Farmers are being paid a 5-year land rent
similar to existing commercial rents in the region, which range from US$ 25-40
acre-1 (CAN$ 93-148 ha-1) Custom operators have been
hired to perform the field work. Yields ranging from 5-10 Mg ha-1yr-1
are anticipated on the heavy clay soils in northern New York. Maximum yields
have attained 9 Mg ha-1yr-1 in 1998. No insect or disease
problems have been experienced to date.
Over the next 10 years, according to Wright and
Tuskan (1997), commercialization of the SRF willow program appears to be a high
risk as the only current market interest is from the electrical energy sector,
provided production costs can be reduced to CAN$ 33 Mg-1. The future
of this afforestation program appears less promising than in other regions in
the northern U.S., mainly because of its heavy reliance on the electrical
energy industry, preventing a larger scale-up of acreage in New York, as the
electrical market appears tenuous (Wright and Tuskan, 1997). This problem has
been exacerbated by the recent change in ownership of NY State Electric and
Gas, which has dropped out of the consortium, and the impending sale of Niagara
Mohawk (which is focussing on electrical distribution and is accordingly in
the process of selling its fossil-based generation capacity). (Fillhart, 1999).
Other higher value energy markets, such as small commercial wood chip heating
systems, or willow conversion into fuel pellets, may hold more potential for
development of the afforestation program.
7.3. Experience in Canada
Currently, there are three important
afforestation programs underway in Canada with fast growing trees. The earliest
program to evolve was in southern British Columbia in the late 1950’s by the Scott
Paper company. This was followed by a program in eastern Ontario, by Domtar
Inc. in the 1970’s. The most recent interest in poplar plantings has been
in northern Alberta, which has been led by ALPAC. A smaller
afforestation program is also occurring in Québec, but requires more industry
support such as that in the other three provinces. Elsewhere in Canada, very
little commercial activity is underway.
7.3.1. Ontario
The government of Ontario funded a large
research and development program for hybrid poplars in eastern Ontario from the
early 1970’s to the mid 1990’s. The focus of the afforestation program was to
establish abandoned and low quality farmland with poplar to supply Domtar’s
Cornwall pulp and paper mill. Currently the program consists of 1,000 ha of
privately-leased lands and 1,200-1,500 ha of Domtar-owned lands, managed
by the Ontario Ministry of Natural Resources. This arrangement is under review
where control of all lands will likely be reverted to Domtar.
The program peaked in the 1980’s, and was one of
the leading programs in North America in the development of fast growing hybrid
poplars. Much effort was placed into improving poplar silviculture techniques
and improving poplar germplasm. The program was led by the fast growing forests
group of the Ministry of Natural Resources in Brockville and received plant
genetic material development support from the University of Toronto. The
afforestation program experienced mixed success: some of the problems
encountered included sites with poorly drained soils which proved unsuitable
for poplar cultivation, and septoria canker caused mortality on a high number
of clones particularly on the drier sites. The typical production scheme that
evolved for pulp and paper production was to plant trees in a spacing of 3 m x
3 m (or 2.4 m x 3.6 m which facilitated inter-row cultivation with a larger
tractor). Cuttings 25 cm long were hand planted in early spring at a density of
1,100 trees ha-1. Plantations tended to be small as abandoned fields
in eastern Ontario are typically 1-3 ha in size, with natural hedgerows between
fields, therefore plantation sizes varied between 0.5 ha - 12 ha. The land was
leased at $27-30 ha-1yr-1 with an option to renew or opt
out after the 12-13 year life-span of the stand.
Domtar has made many changes to the program over
the past 5 years to improve poplar performance. Septoria resistant clones have
been planted and slow-performing clones have been eliminated. Poplar plantings
are being renewed on productive sites with soil conditions suitable for poplar
cultivation, which include silty soils and flood plains. Dry sites are being
improved for moisture holding capacity through the application of a biosolid
stemming from the secondary waste treatment facility. Some coppicing is being
conducted on the desirable poplar clones, however, it is generally too costly
to thin regularly. During the harvesting process a new flail delimber has been
introduced which reduces losses due to limbing, topping and debarking. Current
yield estimates on moderately productive sites are in the range of 3.5-4.6 od
Mg ha-1yr-1 delivered to the mill, or approximately 45-60
od Mg ha-1 on a 12-14 year rotation. Sites with natural regeneration
(primarily ash, but also oak, maple, butternut and hickory) are not being
replanted.
7.3.2. British Columbia
The southern mainland of British Columbia is
home to Canada’s fastest growing poplar trees. The earliest poplar planting
program was initiated by Scott paper in the 1950’s. The company
currently has 2,000 ha of plantings mainly on provincial crown land and company
owned land. On agricultural sites, densities of 800-900 stems per hectare are
planted and harvested on 15 year rotations. The low density is used to
facilitate the production of larger sized trees for ease of handling at their
pulp facility. Cuttings of 45 cm length are used to encourage better early
growth and to ease weed management problems. No serious pest problems have been
experienced. Productivity on former agricultural sites is 6.6-10 od Mg ha-1yr-1
of merchantable timber.
However, the major scale up of the crop was then
subsequently performed by MacMillan Bloedel. Research plantings were
initiated by the company in the early 1980’s with approximately 80% of the
upscaling conducted over the past 4-5 years. The poplar planting program in
British Columbia also received some technical support from the British Columbia
Ministry of Agriculture. A total of 1,600 ha of plantings have been undertaken
by Macmillan Bloedel’s subsidiary, Poplar Farms Inc., in British
Columbia and a further 2,300 ha on the coastal side of the Cascade Mountains of
Washington State. In the U.S., the plantations are managed on a 9-year
rotation and in Canada the rotation length is approximately 12 years due to the
shorter growing season and less fertile soils. Rotations of 12 years or less
qualify for a lowering of the tax status on the land for agricultural purposes.
Density of the plantings was initially 1,000-1,200 stems ha-1,
however this has subsequently been increased to 1,300 stems ha-1.
In Canada merchantable fibre yields of 10-13 od Mg ha-1yr-1
are expected. The harvesting process which tops the trees, debranches and
debarks, leaves 8-9% of this biomass as residual material on the site. Leases
on rented land average approximately $110 ha-1yr-1 (with
a range of $100-$140). The primary commercial market for the material is a
“high brights” paper chip product from MacMillan Bloedel’s pulp and
paper mills. The afforestation program is currently in a state of flux as Macmillan
Bloedel has recently divested from the pulp and paper industry, and Poplar
Farms Inc. was sold along with the paper division to the paper company Pacifica.
Poplar Farms Inc. is currently for sale by the new owners.
The major problem with the British Columbia
afforestation program is the limited land base available in Southern British
Columbia. No more than 10,000 ha of additional land is foreseen to be available
for poplar plantings (Stenersen, 1999; Van Oosten, 1999).
7.3.3 Alberta
The most rapidly developing hybrid poplar
program in Canada is occurring in Alberta. The program, led by ALPAC, in
Boyle, has established 200 ha of operational and research trials since 1993.
The company forecasts to plant 20,000-25,000 ha to supply 15%-25% of the 2.5
million m3 annual supply required for its large single line pulp and
paper mill in Boyle. Other forest product industries are also beginning trials.
A Western Boreal Aspen cooperative has been formed which includes ALPAC,
Weyerhaeuser, Ainsworth Lumber, Daishowa-Marabini America,
Slave Lake, Miller Western and Slocan. Research on genetic
improvement on hybrid poplars is being coordinated by the University of
Alberta. Currently, the program is importing improved clone material and
examining the possibility of establishing a breeding cooperative. The
cooperative plans to evaluate both hybrid poplar and aspen, the latter species
has achieved favourable yields of 15 m3 ha-1 yr-1
(5 odt ha-1yr-1) in Sweden (Thomas 1999).
The major incentive for the development of the ALPAC
program was the concern about fibre supply. The company forecasts a 25% loss of
its land base during the next rotation due to oil and gas claims, land claims
and fire. The company expects to average field growth of 12 m3 ha-1yr-1
(4 Mg ha-1yr-1) over a 20-30 year life-span. The yield
estimates are somewhat speculative as very limited field experience with hybrid
poplars has occurred in this short growing season area with moderate rainfall.
Planting of approximately 1,000-1,400 ha-1yr-1 are
planned to take place in a 200-250 km radius of the Boyle pulp mill. Contracts
will be carried out on a lease arrangement with local landowners or a potential
joint venture agreement.
The company believes that plantations can help
them control fibre costs for their mills in the future. ALPAC’s current
cost of fibre is $30-35 m-3, with an average cycle time (the time to
bring wood to the mill and make the return run) of 9-10 hours with runs up to
15 hours. The wood price is expected to climb to $41-45 m-3 over the
next 20 years and plantation wood is expected to be below the lower range of
this value and have cycle times of less than 5 hours.
7.4
Conclusion
Revisiting the three features required for successful
plantings (perceived need, requisite talent, and suitable land base), none of
the current Canadian regions are able to combine the level of suitability as
that of the North Central region of the U.S.. British Columbia has a strong
fibre demand, sufficient requisite talent (with support from the Pacific
Northwest), however it lacks an adequate land base. Unquestionably, Alberta has
a strong fibre demand, is building its human resource and genetic base, but is
far from certain that relatively slow growing trees on 20-30 year rotations
will prove to be a profitable venture. Eastern Ontario lacks a strong market
demand due to the current surplus of hardwood fibre. It has a good land base
availability, human resources available, as well as an existing germplasm base
for scaling up, should a larger program be initiated. While Québec has no major
afforestation program currently underway, it may present the best opportunity
for SRF programs in Canada, at present. There is a stronger market demand than
in Ontario, human resources and genetic material for developing the industry
are present, and a relatively suitable agricultural land base is available.
Market demand and land availability in Nova Scotia and Manitoba could also
create opportunities for poplar plantings but there has been little previous
experience with the crop in these regions. Finally, an analysis should be
performed to assess the cost of fibre production in Canada versus fast growing
trees in tropical countries to determine the viability of investing in
plantations.
Literature Cited
Fillhart, R. 1999. Personal communication.
Thomas, B. 1999. Personal communication.
Stenersen, K. 1999. Personal communication.
Van Oosten, C. 1999. Personal communication.
Wright
L.L., Tuskan, G.A. 1997. Strategy, results and directions for woody crop
research funded by the US Department of Energy. 1997 Pulping Conference, TAPPI
Journal: 791-799.
Addresses of Contacts
British Columbia
Charlie Burrel,
Poplar Farms
Division of Pacifica Paper Company
Port Alberni, BC
Ken Stenerson
Scott Paper ltd.
P.O. Box 760
New Westminster, BC.
V3L 4Z9
C. Van Oosten,
Silvi-Consult Woody Crops Technology Inc.
P.O. Box 760
New Westminster, BC
V3L 4Z9
Tim Bylander
Weyerhauser
Drayton Valley, Alberta
Dave Cheyne
Slocan Forests Products
Taylor, British Columbia
Allan Robertson
ALPAC, Box 8000
Boyle, Alberta
TOA OMO
Barb Thomas
Genstat Consulting
5211 Landsdowne Drive
Edmonton, Alberta
Ontario
Andy Kenney
University of Toronto
Toronto, Ontario
George Velema,
Domtar Forest Products
P.O. Box 40
Cornwall, Ontario K6H 5S3
Wayne Young
Domtar Forest Products
P.O. Box 40
Cornwall, Ontario K6H 5S3
Adam Zelenski,
Domtar Forest Products
P.O. Box 40
Cornwall, Ontario K6H 5S3
North Central
Ed Wene
Agricultural Utilization Research Institute
Crookston, Minnesota
Don Reimenschneider
USDA, Forest Service
Forest Sciences Laboratory
5985 Highway K
Rhinelander, Wisconsin 54501
Ron Fillhart
State University of New York
College of Environmental Science and Forestry
1 Forestry Drive
Syracuse, New York 13210
Pacific Northwest
Jerry Tuskan
Biofuels Development Program
Oak Ridge National Laboratory
P.O. Box 2008
Oak Ridge, Tennessee 37831-6422
General Conclusion
The emphasis of this analysis was on the carbon
sequestering potential of fast growing trees. In particular, to summarize the
knowledge in areas where little previous information is available. The analysis
attempted to develop realistic estimates of fast growing forest species’ growth
potential in Canada, based on literature searches of existing published
commercial and field plot data, as well as discussions with industry people,
foresters and scientists. As well, a complete analysis of root biomass
accumulation and impact of fast growing trees on soil carbon accumulation in
temperate SR tree plantations was provided. An overview was also provided of
the current status of the technology of fast growing trees, environmental
issues and current afforestation programs. An assessment of the energy and
fibre market opportunities was also undertaken. However, a thorough overview of
these opportunities was not within the scope of the study. More emphasis was
placed on the energy aspects of the material, not because this is where the
greater commercial market opportunities are at present, but because this is
where the greatest greenhouse gas abatement potential exists.
Overall, the study indicated that the least
risky strategy to rapidly implement afforestation programs, for carbon
sequestration in Canada, involved the production of SR hybrid poplars for fibre
applications. Commercial risk with poplars is reduced compared to SR willow
plantations, as SR poplars are already grown for fibre in North America and
competitive market prices for the chips is approximately twice that for energy
applications. This can be achieved, while at the same time incurring costs of
carbon sequestration similar to those of willows. The main limitation of the
study is that the carbon offset occurring over the complete life-cycle of the
biomass produced from hybrid poplar and willow is not estimated. Willows are
less expensive to grow than hybrid poplars, and from that standpoint, are
closer to commercialization for energy applications. Since the greatest carbon
offset benefit from SR tree species may be from fossil fuel displaced in the
case of bioenergy production, life-cycle analysis should be performed for
willow directed towards wood chip and wood pellet heating systems.
