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The Burning Question: Does Forest Bioenergy Reduce Carbon Emissions? A Review of Common Misconceptions about Forest Carbon Accounting


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Critical errors exist in some methodologies applied to evaluate the effects of using forest biomass for bioenergy on atmospheric greenhouse gas emissions. The most common error is failing to consider the fate of forest carbon stocks in the absence of demand for bioenergy. Without this demand, forests will either continue to grow or will be harvested for other wood products. Our goal is to illustrate why correct accounting requires that the difference in stored forest carbon between harvest and no-harvest scenarios be accounted for when forest biomass is used for bioenergy. Among the flawed methodologies evaluated in this review, we address the rationale for accounting for the fate of forest carbon in the absence of demand for bioenergy for forests harvested on a sustained yield basis. We also discuss why the same accounting principles apply to individual stands and forest landscapes.
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harvesting & utilization
The Burning Question: Does Forest Bioenergy
Reduce Carbon Emissions? A Review of
Common Misconceptions about Forest
Carbon Accounting
Michael T. Ter-Mikaelian, Stephen J. Colombo, and Jiaxin Chen
Critical errors exist in some methodologies applied to evaluate the effects of using forest biomass for bioenergy
on atmospheric greenhouse gas emissions. The most common error is failing to consider the fate of forest carbon
stocks in the absence of demand for bioenergy. Without this demand, forests will either continue to grow or will
be harvested for other wood products. Our goal is to illustrate why correct accounting requires that the difference
in stored forest carbon between harvest and no-harvest scenarios be accounted for when forest biomass is used
for bioenergy. Among the flawed methodologies evaluated in this review, we address the rationale for accounting
for the fate of forest carbon in the absence of demand for bioenergy for forests harvested on a sustained yield
basis. We also discuss why the same accounting principles apply to individual stands and forest landscapes.
Keywords: bioenergy, no-harvest baseline, reference point baseline, carbon sequestration parity, carbon
debt repayment, dividend-then-debt, stand versus landscape, plantations
Interest in industrial-scale bioenergy
production using forest biomass is part
of a larger movement to reduce climate
change by using renewable energy in place of
fossil fuels. However, if climate change mit-
igation is indeed a driver for using forest bio-
energy, then this energy source must be as-
sessed for its effects on the greenhouse gas
(GHG) concentration in the atmosphere.
Misconceptions and errors in methodolo-
gies continue to affect this topic, both in the
scientific and “gray” literature (e.g., maga-
zines, reports, and opinion letters), despite
having been addressed in prominent publi-
cations (e.g., Searchinger et al. 2009, Haberl
et al. 2012). A common misconception is
that forest bioenergy is immediately carbon
neutral, with no net GHG emissions as long
as the postharvest forest regrows to its pre-
harvest carbon level. From a forest manag-
er’s perspective, this logic can be appealing
because it appears to fit a sustained yield par-
adigm. But, as we shall show, this paradigm
fails to account for other aspects of bioen-
ergy use needed for proper assessment of its
effect on GHG emissions.
The purpose of this review is to present
the theory and principles for correctly assess-
ing the GHG effects of forest bioenergy. We
discuss common errors that appear in the
forest bioenergy literature and explain why,
in the absence of forest management to in-
crease forest carbon before bioenergy har-
vesting, the use of forest bioenergy often in-
creases atmospheric carbon dioxide (CO
at least temporarily.
Principles of Forest Bioenergy
GHG Accounting
The primary consideration in GHG ac-
counting for forest bioenergy is to accurately
determine the fate of forest biomass in the
absence of demand for its use to produce
bioenergy. This theme will be repeated
throughout this article, because failure to
correctly address this consideration is the
Received February 4, 2014; accepted October 23, 2014; published online November 27, 2014.
Affiliations: Michael T. Ter-Mikaelian (, Ontario Forest Research Institute, Sault Ste. Marie, ON, Canada. Stephen J. Colombo
(, Ontario Forest Research Institute. Jiaxin Chen (, Ontario Forest Research Institute.
Acknowledgments: We thank Lisa Buse (Ontario Ministry of Natural Resources) for editing the earlier version of this article. We also thank the editor-in-chief, associate
editor, and four anonymous reviewers, whose valuable comments helped us improve the article.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Noncommercial License (
licenses/by-nc/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. For
commercial reuse, please contact the Journal of Forestry at
Journal of Forestry January 2015 57
J. For. 113(1):57–68
Copyright © 2015 The Author(s)
cause of most errors in forest bioenergy ac-
When tree biomass is burned for energy
production, sequestered carbon is released to
the atmosphere, mainly as CO
. Typical
sources of forest biomass for biofuel produc-
tion include standing live trees, harvest resi-
due, biomass recovered during salvage oper-
ations, thinnings and residue from thinning
operations, and mill processing residue (e.g.,
sawdust and wood chips); here and through-
out the text, biofuel and bioenergy refer to
fuel produced from live or dead biomass and
to energy derived from burning of biofuel,
respectively. Forest carbon is contained in
live trees, understory vegetation, and in
aboveground (standing dead trees, down
woody debris, and forest floor) and below-
ground dead organic matter (mineral soil
and dead roots). The processes determining
changes in carbon pools include growth and
mortality of live trees, decomposition of
dead organic matter, and its combustion if
burned. Tree growth and mortality are the
main driving forces determining changes in
carbon pools. Live trees transfer carbon to
dead organic matter pools through self-
pruning and mortality; in turn, dead organic
matter pools release carbon to the atmo-
sphere through decomposition. In temper-
ate and boreal forests, the largest amount of
carbon in a forest is typically contained in
live trees and mineral soil, followed by forest
floor, with other pools normally accounting
for less than 15% of total forest carbon (Pan
et al. 2011).
Given the large amounts of woody bio-
mass that stands accumulate, it is intuitive
that carbon accrues as they mature (Figure
1). After a stand-replacing disturbance,
stand-level forest carbon stocks usually de-
crease, because carbon losses from decom-
posing dead organic matter are temporarily
not compensated for by carbon sequestered
by live trees that are still small. As trees grow,
the pattern of net carbon accumulation is
sigmoidal, characterized by initially rapid
increases that slow as a stand reaches matu-
rity (Figure 1). The slowdown in stand net
carbon accumulation at maturity results
from the death of individual trees with on-
going growth distributed among the re-
maining live trees.
Figure 2A shows the accumulation of
carbon in live trees in the absence of harvest.
Harvesting a stand for bioenergy removes
most live tree carbon, leaving unutilized bio-
mass on site, which in traditional harvesting
includes stumps, branches and tops, and
roots. In temperate and boreal forests, recov-
ery of live tree carbon stocks takes decades
because of slow stand regrowth after harvest
(Figure 2B). Forest carbon stocks following
harvest for bioenergy constitute a forest bio-
energy scenario (black line in Figure 2B). For-
est carbon in the absence of demand for bio-
energy represents a forest baseline scenario
(red line in Figure 2A and D); in some liter-
ature reports on forest bioenergy, the forest
baseline scenario is referred to as either
“business-as-usual,” “counterfactual,” or
“protection scenario.”
Forest bioenergy production involves
the use of fossil fuels, resulting in GHG
emissions that are estimated using life cycle
analysis (LCA). An LCA accounts for emis-
sions associated with all phases of bioenergy
production and use (the so-called “cradle-
to-grave” approach): silvicultural activities,
use of logging equipment, transportation of
harvested biomass to a biofuel processing fa-
cility, conversion of biomass into biofuel,
transportation to the energy plant, and non-
products of combustion (e.g., Zhang et
al. 2010). This is the GHG “cost” of pro-
ducing and using forest bioenergy. The LCA
of forest bioenergy does not include CO
GHG emissions from biofuel combustion,
because these emissions are accounted for
when the effects of bioenergy demand on
carbon in forest stocks are evaluated
(Figure 2C).
When forest bioenergy displaces energy
from a fossil fuel, it eliminates GHG emis-
sions from producing and burning the fossil
fuel (the reference fossil fuel scenario). The
LCA for a fossil fuel includes all GHG emis-
sions from obtaining and processing the
fuel, but, unlike bioenergy, the fossil fuel
LCA also includes all GHG emissions from
combustion (Figure 2C). The difference in
LCA emissions between forest bioenergy
and a fossil fuel constitutes the GHG benefit
of displacing this fossil fuel with forest bio-
energy (Figure 2C and D).
Management and Policy Implications
A growing market for energy produced from forest biomass has arisen because of the potential to mitigate
climate change by replacing fossil fuel energy. However, managers who want to access this market should
be aware that the benefits of forest bioenergy depend on evaluation of forest management options
against a baseline scenario considering what happens to carbon stocks if biomass is not harvested for
energy. Among the more favorable options are the use of residue from ongoing harvest operations for
traditional wood products (lumber and pulp) and application of intensive silviculture to regeneration of
harvested stands. Establishment of new bioenergy-designated plantations on abandoned/degraded lands
requires more time for forest biomass to become available for harvest but has the advantage of a low
carbon stock value baseline. The least favorable options include harvest of standing live trees, both in
addition to and in lieu of ongoing harvest operations for traditional wood products. Policies for bioenergy
use also need to recognize that accounting for emission benefits when fossil fuels are replaced requires
accounting for forest carbon (either in forest or in traditional wood products) that would have continued
to exist if fossil fuels were not replaced by bioenergy.
Figure 1. Typical change in forest carbon stocks after stand harvest (modified from Ter-
Mikaelian et al. 2014a). Dark and light gray areas represent carbon stocks in live biomass
and dead organic matter (DOM), respectively.
58 Journal of Forestry January 2015
Thus, accounting for the GHG emis-
sion reduction potential of forest bioenergy
must include the following:
A. Forest carbon following biomass harvest
for energy production (the forest bioen-
ergy scenario);
B. Forest carbon in the absence of demand
for bioenergy (the forest baseline sce-
C. Life cycle GHG emissions (upstream
fossil fuel emissions) from producing
forest bioenergy (excluding GHG com-
bustion emissions); and
D. Life cycle GHG emissions (including
those from combustion) for the fossil
fuel displaced by forest biomass (the ref-
erence fossil fuel scenario).
Components A and B are required to assess
emissions to the atmosphere or lost po-
tential CO
sequestration resulting from ex-
tracting biomass from the forest to meet the
demand for bioenergy, relative to that with-
out bioenergy demand (i.e., no harvest).
Component C (LCA of bioenergy produc-
tion) includes GHG emissions from pro-
ducing the biofuel and its use in place of a
fossil fuel; it includes non-CO
from biomass combustion but not CO
emissions, which are accounted for in com-
ponents A and B. Finally, component D
(LCA of the reference fossil fuel) is required
to assess the GHG emission benefits of dis-
placing fossil fuel use with forest bioenergy.
Component A should include losses of
forest carbon stocks due to the construction
of access roads to harvest sites. Similarly, up-
stream emissions for fossil fuel-based energy
(component D) may require accounting for
changes in forest carbon stocks if extraction
of fossil fuels is associated with forestland
cover changes due to mining and road con-
struction. While such losses of forested area
in North America may be small at the re-
gional and national scales (e.g., Sleeter et al.
2012, Natural Resources Canada 2013),
their local effect on forest carbon stocks can
be significant (e.g., Campbell et al. 2012,
Drohan et al. 2012).
It should be noted that this review fo-
cuses primarily on solid biofuels used for
combustion for heat and electricity genera-
tion. Although second-generation biofuels
(e.g., bioethanol for vehicular use, and bio-
gas) made from wood are currently not com-
mercial energy sources (Naik et al. 2010,
Bonin and Lal 2012), early research suggests
that wood has a potential to become the
Figure 2. Effect of harvest for bioenergy used to replace coal on forest carbon stock changes
and total greenhouse gas (GHG) emissions (stand level, from Ter-Mikaelian et al. 2014b).
A. Accumulation of carbon in an unharvested forest stand. B. Carbon in the stand regen-
erating after harvest. C. Harvested biomass is used to produce wood pellets; life cycle GHG
emissions from obtaining and producing wood pellets are lower than life cycle and
combustion emissions of coal, resulting in a GHG benefit of using wood pellets to replace
coal. D. Carbon sequestration parity is achieved when the sum of carbon in the regener-
ating stand and the GHG benefits of using wood pellets to replace coal reaches the amount
of carbon in the stand if it had remained unharvested; carbon debt repayment is achieved
when the sum of carbon in the regenerating stand and GHG benefits of using wood pellets
to replace coal reaches the preharvest amount of carbon in the stand.
Journal of Forestry January 2015 59
main feedstock for production of liquid and
gaseous biofuels (Hedegaard et al. 2008,
Havlik et al. 2011). However, the principles
for assessing the GHG effects of liquid and
gaseous biofuels, in particular the methodol-
ogy to account for changes in forest carbon
stocks are the same as those described above.
The difference between components A
and B constitutes the change in forest carbon
stocks resulting from biomass harvest for
bioenergy; the difference between compo-
nents C and D indicates the GHG benefit of
replacing a reference fossil fuel with forest
bioenergy (Figure 2C). The estimated total
GHG emissions caused by demand for bio-
energy to replace fossil fuel are given by
Total GHG emissions
Change in forest carbon stocks
GHG benefit of replacing fossil
fuel with forest bioenergy (1)
For a detailed mathematical form of Equa-
tion 1, see McKechnie et al. (2011). This
numerical approach is used for an individual
stand. The same approach is used for a forest
landscape in which the annual biomass har-
vest is used to produce energy by integrating
Equation 1 over time, starting from the first
year of biomass collection.
The LCA of bioenergy and fossil fuel-
based energy production usually includes
emissions of CO
and two other GHGs:
methane (CH
) and nitrous oxide (N
(Intergovernmental Panel on Climate
Change [IPCC] 2006). Non-CO
emissions are converted into CO
lents based on their global warming poten-
tial (GWP) (IPCC 2007). Despite growing
criticism (e.g., Shine 2009, Fuglestvedt et al.
2010), GWP factors remain the standard
approach for assessing the effects of GHGs
on climate change (IPCC 2007). The
amount of CH
and N
O (in units of mass)
released during combustion of biofuels and
fossil fuels is several orders of magnitude
lower than that of CO
(IPCC 2006). Re-
lease of these GHGs may also result from
nitrogen fertilizer application (N
O emis-
sions) and organic matter decomposition in
soil (CH
and N
O emissions) (Cherubini
et al. 2009).
Accounting for changes in forest carbon
stocks relative to the baseline scenario is par-
amount for proper assessment of bioenergy
GHG emissions: without demand for bio-
energy, harvesting either does not occur and
the forest continues growing and sequester-
ing additional carbon or it is harvested for
traditional wood products (lumber and
pulpwood). This is also true when bioenergy
replaces fossil fuel energy: replacement of
fossil fuels means harvest for bioenergy,
whereas no replacement of fossil fuels means
no harvest for bioenergy. This link results in
an inextricable connection between the ref-
erence fossil fuel and forest baseline scenar-
ios: accounting for GHG benefits when
fossil fuels are replaced requires account-
ing for forest carbon losses (either in forest
or in traditional wood products) that
would not have occurred if use of fossil
fuels continued.
At the onset of biomass harvesting for
bioenergy, the total GHG emissions in
Equation 1 are usually negative because the
reductions in forest carbon outweigh the
GHG benefits of displacing fossil fuel with
forest bioenergy. Over time, however, net
GHG emissions in the forest bioenergy sce-
nario become smaller as harvested stands re-
generate and sequester carbon (Figure 2D).
The point at which the change in forest car-
bon (the difference between forest carbon in
the bioenergy and baseline scenarios) equals
the accumulated GHG benefit of using for-
est bioenergy in place of fossil fuel is called
carbon sequestration parity (Mitchell et al.
2012). Consequently, the time from begin-
ning biomass harvest to carbon sequestra-
tion parity is called time to carbon sequestra-
tion parity. Only after passing the time to
carbon sequestration parity does forest bio-
energy reduce atmospheric GHG compared
with the reference fossil fuel scenario.
Time to carbon sequestration parity is
also referred to as the “carbon offset parity
point” (e.g., Jonker et al. 2014, p. 371),
“break-even period” (e.g., Ter-Mikaelian et
al. 2011, p. 644), or “time to carbon neutral-
ity” (Domke et al. 2012, p. 146). We prefer
the term carbon sequestration parity rather
than carbon neutrality because the latter has
been defined in a variety of ways (National
Council for Air and Stream Improvement
[NCASI] 2013).
Time to carbon sequestration parity de-
pends on factors such as the source of forest
biomass (e.g., standing live trees versus har-
vest residue), growth of regenerating stands
after harvest, and emissions from the refer-
ence fossil fuel. The peer-reviewed literature
contains many studies with estimates of time
to carbon sequestration parity for forest bio-
energy replacing coal (e.g., McKechnie et al.
2011, Ter-Mikaelian et al. 2011, Holtsmark
2012, Repo et al. 2012, Jonker et al. 2014,
Lamers et al. 2014), natural gas (Domke et
al. 2012), oil (Repo et al. 2012), and auto-
motive gasoline (Hudiburg et al. 2011).
These studies consistently show that har-
vesting live trees to produce bioenergy ini-
tially increases GHG emissions, which may
take decades to centuries to offset. However,
it has also been shown that intensive forest
management of areas harvested for bioen-
ergy may substantially reduce time to carbon
sequestration parity (e.g., Jonker et al. 2014,
Ter-Mikaelian et al. 2014b).
Figure 3 presents carbon stock changes
and GHG emissions for the scenario of an-
nual demand for bioenergy being met by
harvesting standing live trees on a landscape
scale to displace coal-fired power generation
(from McKechnie et al. 2011). The study
Figure 3. Changes in forest landscape carbon stocks (dotted line), cumulative total GHG
emissions (solid line), and GHG benefits (dashed line) from displacing coal with bioenergy
generated from harvest of standing live trees (modified from McKechnie et al. 2011).
Positive values correspond to emissions, whereas negative values show removals (seques-
tration) of carbon from the atmosphere.
60 Journal of Forestry January 2015
area covered a total of 52,494 km
in the
Great Lakes-St. Lawrence forest region (On-
tario, Canada); the supply of biomass came
from clearcut harvesting of low-intensity
managed stands composed of a mix of hard-
wood (sugar maple, yellow birch, and red
oak) and softwood (jack pine, black spruce,
and balsam fir) species. Emissions from re-
duced forest carbon stocks initially outweigh
GHG benefits, resulting in positive GHG
emissions overall (solid line above zero in
Figure 3, indicating increased atmospheric
). The trend is reversed by continued
accumulation of GHG benefits from fossil
fuel displacement and plateauing of land-
scape losses in forest carbon, although car-
bon sequestration parity (and net atmo-
spheric reduction of GHG) is not reached
until 38 years after harvesting begins (the
time at which the solid line crosses below the
zero line), beyond which total GHG emis-
sions are negative (solid line below zero in
Figure 3), indicating net removal of CO
from the atmosphere.
The approach we describe is based on
counting carbon fluxes between the bio-
sphere and atmosphere, referred to as a mass
balance or carbon balance approach (Sathre
and Gustavsson 2011). For approaches that
enhance the mass balance approach by ac-
counting for the timing of GHG emissions
and radiative forcing, the reader is referred
to Sathre and Gustavsson (2011), Cherubini
et al. (2011), Repo et al. (2012), and Agos-
tini et al. (2013).
Review Scope
Studies accounting for the GHG effects
of forest bioenergy are characterized by spa-
tial and temporal boundaries, type of LCA,
and forest baseline and reference fossil fuel
scenarios (Helin et al. 2013). This review
pertains spatially to studies of forest land-
scapes managed for bioenergy production.
We focus primarily on accounting for the
carbon effects of harvesting standing live
trees for bioenergy, because this biomass
source has the greatest potential to produce
large, long-lasting effects on the atmospheric
carbon concentration. Nevertheless, the
same basic premises for determining the at-
mospheric effects of bioenergy apply to
other sources of biomass and are also dis-
The spatial boundary used in bioenergy
GHG accounting is interrelated with the is-
sue of land-use change (LUC), which can be
either direct or indirect (Berndes et al. 2010,
Bird et al. 2011). Direct LUC involves
changes on the land where bioenergy feed-
stock production occurs, such as a change
from farmland to bioenergy plantation. In-
direct LUC refers to changes in land use that
take place elsewhere as a consequence of har-
vesting for bioenergy. An example of indi-
rect LUC is conversion in another country
of natural forest to farmland in response to
the above direct LUC, where farmland in
the study area was converted to a bioenergy
plantation. Here, we focus on forest land-
scapes managed for bioenergy production;
indirect LUC associated with forest bioen-
ergy production is discussed in a section of
this review devoted to that topic.
Bioenergy LCAs can be attributional or
consequential (Brander et al. 2008, Lippke
et al. 2011, Helin et al. 2013). An attribu-
tional LCA provides information about the
direct effects of processes used for a given
product (e.g., production, consumption,
and disposal) but does not consider indirect
effects arising from changes in the output of
a product (Brander et al. 2008). Studies in-
cluded in this review use a consequential
LCA approach, because they assess the con-
sequences of changes in the level of output of
a product, including effects both inside and
outside the life cycle of the product (Brander
et al. 2008). Some reports (e.g., NCASI
2013) erroneously suggest that the conse-
quential LCA approach is appropriate only
for large-scale evaluations of forest carbon
policies. In reality, all bioenergy studies re-
viewed here, regardless of their scale and ob-
jective, use a consequential LCA approach,
at least partially. Indeed, it is most common
to include reference fossil fuel scenarios to
demonstrate the GHG benefits of using for-
est bioenergy. This inclusion automatically
places such studies in the category of a con-
sequential LCA approach, because fossil fuel
displacement occurs as a consequence of for-
est bioenergy use.
This review considers three potential
forest baseline scenarios: the no-harvest base-
line, constituting the natural evolution of
the forest in the absence of harvest for bio-
energy; the traditional wood products base-
line, in which forest in the absence of harvest
for bioenergy is harvested for traditional
wood products (lumber and pulpwood); and
the reference point baseline, which will be in-
troduced later in this review. Of the three
baselines, the no-harvest baseline appears to
be at the core of many misconceptions dis-
cussed in this review. This baseline is also
referred to as an “anticipated future base-
line” (e.g., AEBIOM 2013, p. 5), a “biomass
opportunity cost baseline” (Johnson and
Tschudi 2012, p. 12), and a “natural relax-
ation baseline” (Helin et al. 2013, p. 477).
We prefer the term no-harvest baseline be-
cause it intuitively suggests what happens to
the forest in the absence of harvest for bio-
energy. Other baselines considered in the lit-
erature, such as the comparative baseline
(US Environmental Protection Agency
2011) and the marginal fossil fuel baseline
(Johnson and Tschudi 2012), combine for-
est and reference fossil fuel baselines to esti-
mate net atmospheric balance.
As noted by Helin et al. (2013), there
are no scientific criteria governing what the
time frame for assessing GHG effects of for-
est bioenergy must be, because it depends on
the aims of the assessment. Typically, studies
cover at least one silvicultural rotation, with
the time horizon ranging from several de-
cades to hundreds of years. Unlike tradi-
tional LCA studies, in which results are pre-
sented as one estimate covering the entire
time frame, studies on the GHG effects of
forest bioenergy often provide a temporal
profile of GHG emissions (Helin et al.
2013). It is worth noting, however, that
short- and long-term effects of bioenergy
emissions are likely to be different (Sedjo
2011). Miner et al. (2014) correctly point
out that use of short time frames for assess-
ing the GHG effects of bioenergy is incon-
sistent with application of GWP factors es-
timated over a 100-year period (GWP-100).
Using a fixed time frame of 100 years is ac-
ceptable as long as it is clearly understood
that such estimates of GHG effects will be
realized 100 years after the beginning of bio-
energy production. However, using only a
100-year time frame would obscure time to
carbon sequestration parity, which is an im-
portant indicator of how long it takes forest
bioenergy to start yielding climate mitiga-
tion benefits. In addition, the GWP factor
for N
O is reasonably constant over the first
100 years (e.g., GWP-20 and GWP-100 are
equal to 289 and 298, respectively) (IPCC
2007). The GWP factor for CH
over shorter periods would be higher than
that for 100 years (e.g., GWP-20 and GWP-
100 are 72 and 25, respectively) (IPCC
2007). However, the numerical error in es-
timating time to carbon sequestration parity
introduced by applying GWP-100 to CH
small because of the relatively low amounts
produced during both bioenergy and fossil
fuel energy production (e.g., Zhang et al.
2010; also see the sensitivity analysis in Ter-
Mikaelian et al. 2014b). Next, we examine
Journal of Forestry January 2015 61
common errors in forest bioenergy carbon
accounting using live tree harvest for bioen-
ergy, summarized in Table 1.
Common Errors in Accounting
for Carbon When Using Forest
Renewable Equals Carbon Neutral
One of the earliest misconceptions
about the effects of forest bioenergy is the
erroneous conclusion that forest bioenergy is
carbon neutral because forests harvested for
bioenergy eventually grow back, reabsorbing
carbon emitted during energy combustion.
Although the flaw in this assumption has
been identified repeatedly (e.g., Marland
2010, Agostini et al. 2013), some govern-
ment documents, forest industry reports,
and websites claim that forest bioenergy is
carbon neutral because forests regrow. One
such statement among many found on the
worldwide web is as follows:
The carbon dioxide (CO
) emitted on
combustion of biomass is taken up by new
plant growth, resulting in zero net emis-
sions of CO
bioenergy is considered to
be carbon neutral (Sustainable Energy Au-
thority of Ireland)
Statements such as this one disregard the
time factor for forests to achieve the same
forest carbon level relative to the no-bioen-
ergy demand scenario. Although the state-
ment is generally correct in that the forest
carbon deficit resulting from biomass har-
vest for energy might be eventually offset by
carbon sequestration in regenerating forests,
it is made implicitly incorrect by not ac-
knowledging that decades to centuries are
needed to erase this deficit. In the meantime,
elevated levels of CO
in the atmosphere
have numerous potential direct (indepen-
dent of climate change) and indirect
(through changes to climate) biological con-
sequences (Ziska 2008).
Sustained Yield Equals Carbon
An assumption that bioenergy harvest-
ing in forests managed on a sustained yield
(also called sustainable yield) basis does not
create a carbon deficit is one of the most
common errors in forest bioenergy account-
ing. This argument is often presented as a
“stand versus landscape” approach, imply-
ing that the accounting principles presented
in the previous section of this review are
valid for an individual stand but do not ap-
ply to forest landscapes managed for sus-
tained yield. The stand versus landscape ap-
proach has been discussed in both the peer-
reviewed (e.g., Lamers and Junginger 2013,
Jonker et al. 2014) and non-peer-reviewed
(e.g., Strauss 2011, 2013, Ray 2012,
AEBIOM 2013) literature. The common
argument is that because biomass removal
from a fraction of the area in a sustained
yield landscape is compensated for by
growth in the remaining forest, harvesting
causes no net loss of biomass, which leads to
an incorrect claim that there is no carbon
deficit from bioenergy harvest in a sustained
yield landscape.
Although sustained yield harvesting is a
valid approach in traditional forestry for
providing a steady flow of wood, the claim
that it is carbon neutral can only be made by
ignoring the principles of carbon mass bal-
ance accounting (for examples of incorrect
accounting, see Strauss and Schmidt 2012,
AEBIOM 2013). To repeat these principles,
to claim an emissions reduction from using
forest biomass to produce energy in place of
a fossil fuel, two scenarios must be accepted:
one where fossil fuels are used and forests are
not harvested for bioenergy; and the other
where forests are harvested with the biomass
used for energy generation. Stating that sus-
tained yield management is carbon neutral is
incorrect because it fails to account for the
case involving no harvest for bioenergy in
the reference fossil fuel scenario.
Table 1. Main types of errors in approaches used to assess the carbon effects of forest bioenergy.
Category Rationale for approach Errors in approach
Renewable equals carbon neutral Forest bioenergy is carbon neutral because harvested forest will grow
back and compensate for carbon losses incurred during harvest
Disregards the length of time required for the forest to grow back
and effects of elevated atmospheric carbon concentration
during this period
Sustained yield equals carbon
Carbon losses from harvesting a fraction of a sustainably managed
landscape are compensated for by tree growth in the remaining
landscape, removing the need to account for forest carbon stock
Fails to account for changes in forest carbon stocks in the absence
of harvest for bioenergy (no-harvest baseline scenario)
Commits a methodological error of using only “one-half” of the
reference fossil fuel scenario
Direct diversion from traditional
wood products
In the absence of demand for bioenergy, the forest would be
harvested for traditional wood products, removing the need to
account for forest carbon stock changes
Fails to account for lost carbon storage in traditional wood
products and substitution of these products with more carbon
emission-costly materials (traditional wood products baseline)
Dividend-then-debt Harvest releases carbon previously sequestered from the atmosphere,
therefore beginning the carbon accounting framework when the
forest stand starts to grow “eliminates” the carbon deficit created
by stand harvest (usually proposed in conjunction with sustained
yield approach described above)
Disregards the fact that each stand is preceded by another stand
and thus ignores carbon released by previous harvest, while
crediting the current sequestration
Also involves the errors outlined for the sustained yield approach
(described above)
Plantations for bioenergy Forest carbon stock changes need not be accounted for when
plantations are established purposely for harvest for bioenergy
Currently associated with a largely hypothetical case in the
United States; few plantations were established on nonforested
land for bioenergy; also a partial case of the dividend-then-
debt approach (see above)
Abandoned plantations carry no
carbon debt
Forest carbon stock changes need not be accounted for when
plantations established for traditional wood products are
abandoned because of diminishing market demand for such
products and would likely be deforested
Fails to consider the appropriate baseline scenarios that include
either the no-harvest baseline scenario that could offer a better
carbon emission mitigation option than harvest for bioenergy,
or the deforestation scenario that includes a single harvest for
traditional wood products/bioenergy and carbon stocks in
deforested area
Carbon debt repayment
(reference point baseline)
Changes in forest carbon stocks after harvest for bioenergy are
compared with carbon losses at the time of harvest (often
proposed in conjunction with sustained yield approach described
Fails to account for changes in forest carbon stocks in the absence
of demand for bioenergy (no-harvest baseline scenario)
Involves a methodological error of using only “one-half” of the
reference fossil fuel scenario
62 Journal of Forestry January 2015
Furthermore, in a regulated forest, har-
vested biomass is maximized on a sustained
yield basis when stands are harvested as they
reach the maximum mean annual growth
rate, which occurs before they attain maxi-
mum yield, i.e., if left unharvested the stand
would gain more biomass and consequently
increase live tree carbon stocks for a period
of time (Cooper 1983). A stand may con-
tinue to accumulate carbon stocks even past
the point of maximum fiber yield, because
carbon from dead trees is transferred to dead
organic matter pools, which, depending on
climate, can have slow decomposition rates
(Kurz et al. 2009). Therefore, increased har-
vest applied to an existing regulated (i.e.,
sustained yield) forest landscape results in a
loss of potential carbon sequestration. This
may also be the case in old-growth land-
scapes (Luyssaert et al. 2008), which may
continue to increase total carbon stocks, al-
beit slowly, in the absence of harvesting.
Thus, in a regulated forest landscape, any
harvest (and harvest for bioenergy in partic-
ular) would in all instances result in in-
creased atmospheric CO
for a period of
time due to lost future carbon sequestration.
Such increases in atmospheric CO
be ignored simply because the landscape is
being harvested on a sustained yield basis.
In summary, it is an error to conclude
that bioenergy from a sustained yield forest
is automatically carbon neutral, because, on
the one hand, it accepts carbon emissions
reductions associated with reduced fossil
fuel use, but then fails to acknowledge the
“other half” of the reference fossil fuel sce-
nario; i.e., if fossil fuels are used, then forests
are not harvested for bioenergy.
Diversion from Traditional Wood
An argument can be made that in the
sustained yield approach the no-harvest
baseline does not need to be considered if, in
the absence of demand for bioenergy, forests
would be harvested for traditional wood
products (e.g., lumber and pulp). This argu-
ment may not be relevant, however, because
bioenergy is one of the lowest value uses for
forest biomass and market forces would be
unlikely to result in bioenergy harvest in lieu
of harvest for traditional wood products
(Werner et al. 2010, AEBIOM 2013). Fur-
thermore, even if the choice was made to
harvest for bioenergy, this would shift the
harvest for traditional wood products else-
where (see the section on Indirect LUC),
because many studies predict continued
growth in demand for traditional wood
products both at the national and global
scales (Ince et al. 2011, Daigneault et al.
2012, Nepal et al. 2012, Latta et al. 2013).
If these issues were addressed and a le-
gitimate case was made that forest biomass
was diverted from harvest for traditional
wood products to bioenergy, then the tradi-
tional wood products scenario is the correct
forest baseline (Agostini et al. 2013). This
would include accounting for the large and
long-lasting stock of carbon that is retained
in some traditional wood products (Chen et
al. 2008, 2013). Retention of carbon in
wood products is characterized by product
“half-life”: the time it takes half of a type of
wood product to be removed from service.
Estimates of wood product half-life range
from 67 to 100 years for construction lum-
ber in the United States and from 1 to 6
years for paper (Skog and Nicholson 2000).
After wood product use ends, some carbon
may be emitted to the atmosphere through
decomposition or burning (with or without
producing energy), or wood products may
be recycled or disposed of in landfills. In
landfills, a fraction of the carbon slowly re-
leases to the atmosphere through decompo-
sition, and the rest remains indefinitely due
to its resistance to decomposition (Micales
and Skog 1997). The traditional wood prod-
ucts baseline for building materials and
other solidwood products should also in-
clude the displacement value from using
wood compared with using more CO
sion-intensive materials (Richter 1998,
Gustavsson et al. 2006), so that accounting
for wood used for bioenergy in place of use
in traditional wood products must include
LCA emissions associated with substitution
of wood by nonwood materials (Matthews
et al. 2012).
Proponents of the dividend-then-debt
approach to forest carbon accounting argue
that studies on the effects of forest bioenergy
are incorrect if they use the moment of har-
vest as the starting point for carbon cycle
analysis (e.g., Strauss 2011, Ray 2012). As
stated by Strauss (2013, p. 14),
all of the studies that show that wood-to-
energy adds to the carbon stock of the at-
mosphere assume a carbon debt is created
that has to be repaid by new growth over
3080 years (or more in some studies)
The dividend-then-debt approach is based
on the idea that harvest does not create a loss
of forest carbon because it merely returns
that was previously absorbed by the
trees to the atmosphere. To quote, “carbon
deficit is only real if you ignore the fact that
the trees gobbled up carbon before they were
harvested” (Ray 2012).
However, the dividend-then-debt ap-
proach ignores the fact that, in most cases,
new stands replace previously harvested
stands. Those stands were in turn preceded
by other stands, and so on. Thus, moving
the starting point of carbon accounting
backwards in time to when carbon stocks in
a given piece of land were low takes credit for
the latest cycle of carbon accumulation but
ignores the fact that over time, on average,
forests contain substantial amounts of car-
bon. The point in question in dividend-
then-debt comes down to the original natu-
ral state of the land, which, for most current
forestland, was forest. In that case, it is in-
correct to use dividend-then-debt account-
Plantations Used for Bioenergy Carry
No Carbon Debt
Some studies conclude that forest bio-
energy obtained from plantations that are
already in a sustained yield state carries no
carbon debt because the plantations were
specifically established to be harvested for
bioenergy, and, therefore, all the biomass in
such forests can be considered to have been
grown for the purpose of burning (e.g.,
AEBIOM 2013, Jonker et al. 2014). On this
basis, it is argued that since carbon in such
forests was sequestered for the purpose of
burning, without a bioenergy market they
would never have existed in the first place.
Sedjo (2011) calls this a forward-looking ap-
if trees are planted in anticipation of their
future use for biofuels, then the carbon re-
leased on the burning of the wood was pre-
viously sequestered in the earlier biological
growth process (Sedjo 2011, p. 4)
We contend that this is an acceptable inter-
pretation, but only as long as such planta-
tions were established on deforested land
specifically to be harvested for bioenergy.
However, we are unaware of large existing
areas of plantations in the United States es-
tablished specifically for bioenergy (short-
rotation bioenergy plantations are not un-
common in Europe). For these reasons, the
concept is largely hypothetical, and it is a
mistake to apply this premise to plantations
in general. Furthermore, plantations are
usually established on land that historically
held natural forest, which either was con-
Journal of Forestry January 2015 63
verted to plantation forest or was deforested
and converted to another land use before the
plantation forest was established. In such
cases, bioenergy plantations would be sub-
ject to the criticisms made of the dividend-
then-debt approach if they replace planta-
tions for traditional wood products.
In conclusion, existing plantations used
for bioenergy cannot be considered exempt
from the need to account for carbon using
the mass balance approach described in this
review, although it may be the case in future
for bioenergy plantations established on
long-deforested land.
Abandoned Plantations Carry No
Carbon Debt
Several studies (e.g., Lamers and
Junginger 2013, Jonker et al. 2014) discuss
plantations established for traditional wood
products but “abandoned” due to diminish-
ing fiber demand (referring primarily to the
southeastern United States). They suggest
that protection (no harvest) of such planta-
tions is an unlikely scenario, and more real-
istic alternatives are conversion to agricul-
ture or urban development. Lamers and
Junginger (2013) argue that these planta-
tions should therefore be considered a “free”
source of bioenergy, since deforestation
would be the baseline in the fossil fuel sce-
nario, whereas Jonker et al. (2014) propose
using the carbon debt repayment approach
discussed later in this review. Here we note
that such an approach is in error because it
ignores the fate of forest carbon in the base-
line scenario where there is no harvest for
Although production of certain tradi-
tional wood products (e.g., pulp and paper)
has indeed been declining since 2000 (Hu-
jala et al. 2013), the likelihood of there being
large numbers of abandoned plantations
contradicts national and global projections
of increasing demand for traditional wood
products (Ince et al. 2011, Daigneault et al.
2012, Nepal et al. 2012, Latta et al. 2013).
If, however, there are plantations abandoned
due to regional deviations from global trends
for which the no-harvest baseline is an unre-
alistic scenario, then for such plantations the
appropriate baseline for forest bioenergy sce-
nario is deforestation followed by LUC. Be-
cause it is highly unlikely that the act of de-
forestation results in disposal of standing live
trees as waste, the deforestation baseline
should include a single harvest of standing
live trees and their utilization for either tra-
ditional wood products or bioenergy, with
carbon stocks in deforested areas determined
by the new land use.
To conclude, the correct baseline sce-
narios for abandoned plantations are either
the no-harvest scenario or, where this is
deemed unrealistic, a deforestation scenario
that accounts for the fate of forest biomass
carbon due to deforestation and carbon
stocks in deforested land.
Use of the Carbon Debt Repayment
Approach to Carbon Accounting
The concept of carbon debt repayment
(Mitchell et al. 2012, Jonker et al. 2014)
calls for calculation of the forest carbon def-
icit relative to the amount of forest carbon at
time of harvest. Unlike carbon sequestration
parity, carbon debt repayment, referred to as
“atmospheric carbon parity” by Agostini et
al. (2013, p. 33), assumes that a forest car-
bon deficit created by harvest is completely
repaid once the combined balance of carbon
stocks in the postharvest forest and LCA
benefits from substituting for fossil fuel
equals carbon stocks in the preharvest forest
(Figure 2D).
Recent defense of the carbon debt re-
payment approach was made in a report
published by AEBIOM (2013). In its dis-
cussion of harvest for bioenergy of standing
live trees in southeastern US forests, the no-
harvest baseline is called “completely inap-
propriate” and “unrealistic” and is listed
among the
fundamental flaws in key assumptions and
methodology that underlie prominent
studies that have found forest-based bioen-
ergy to be associated with significant carbon
deficits (AEBIOM 2013, p. 5–6)
Instead, the report advocates using the so-
called “reference point baseline” (p. 36),
which is identical to carbon debt repayment.
Proponents of carbon debt repayment
(such as AEBIOM 2013, Jonker et al. 2014)
make the fundamental error of ignoring the
fate of forests in the reference fossil fuel sce-
nario. As noted earlier, in the fossil fuel sce-
nario, when GHG emissions from fossil fuel
combustion occur, they do so in lieu of bio-
energy, and so carbon stored in forests in-
creases over time. To claim emissions reduc-
tions from avoided fossil fuel use, it is
logically required that forest growth be ac-
counted for in the case where fossil fuels are
used (no harvest for bioenergy is needed).
Therefore, use of the carbon debt repayment
method results in incorrect estimates of bio-
energy GHG emissions.
Indirect LUC
As noted earlier, indirect LUC refers to
changes in land use outside the area man-
aged for bioenergy that occur as a conse-
quence of harvesting for bioenergy (Berndes
et al. 2010, Bird et al. 2011). For this reason,
the spatial scale of bioenergy studies where
indirect LUC is considered typically are re-
gional or national in scope (for examples, see
Abt et al. 2010, 2012, Ince et al. 2011, Galik
and Abt 2012, Daigneault et al. 2012, Nepal
et al. 2012, Sedjo and Tian 2012, Latta et al.
The above cited studies share in com-
mon the use of econometric models to ana-
lyze the effects of market prices and wood
products and bioenergy demand scenarios
on forest growing stock and/or carbon. Car-
bon accounting in these studies often has
serious shortcomings; for example, some do
not account for LCA emissions, whereas
others do not consider forest carbon pools
beyond those in harvested wood. Such
shortcomings can potentially alter whether
or when forest biomass produces a net atmo-
spheric carbon benefit. Generally, and with
these caveats in mind, such studies conclude
that greater bioenergy demand would in-
crease biomass supply and that growth in
forest carbon due to indirect land use effects,
such as increased planting or silviculture,
may outpace forest carbon stock reductions
caused by bioenergy harvest.
In the event that indirect LUC is ac-
counted for, the estimation of GHG emis-
sions attributed to forest bioenergy still re-
quires quantification of forest carbon stocks
in an appropriate forest baseline, as well as
LCA emissions for the bioenergy and refer-
ence fossil fuel scenarios. This is because di-
rect LUC associated with forest bioenergy
(forest landscape managed for bioenergy) is
“nested” in indirect LUC (changes to forest
and/or nonforested areas outside of the
landscape managed for forest bioenergy)
(Berndes et al. 2010). In other words, inclu-
sion of indirect LUC may alter the time to
carbon sequestration parity for a given for-
estry system, but it does not alter the meth-
odology of assessing the forest bioenergy
contribution to GHG emissions from this
system. In addition, it is important to verify
that potential indirect LUC does in practice
occur, taking note of Rabl et al. (2007), who
recommend that emissions and removals of
be accounted for explicitly during each
stage of the bioenergy life cycle. We consider
the recommendation by Rabl et al. (2007)
64 Journal of Forestry January 2015
key, given some highly uncertain potential
consequences to indirect LUC resulting
from increased bioenergy demand.
Other Sources of Forest
Residue from ongoing harvest opera-
tions is the second most common potential
source of biomass considered in the litera-
ture on forest bioenergy. The GHG effects
of using harvest residue for bioenergy have
been studied by several authors (e.g., Mc-
Kechnie et al. 2011, Domke et al. 2012,
Repo et al. 2012). The key difference be-
tween assessing GHG effects of using har-
vest residue versus live trees as a source of
biomass is in the baseline scenario: in the
case of harvest residue, the baseline scenario
must include a projection of the amount of
carbon stored in harvest residue if it were not
collected because of an absence of demand
for bioenergy (an exception to the need to
account for the fate of harvest residue is if it
came from plantations established specifi-
cally for bioenergy production). Conse-
quently, studies not including an analysis of
a residue baseline scenario are bound to
show shorter periods to reach a net reduc-
tion in GHG emissions (e.g., Yoshioka et al.
2005, Froese et al. 2010, Gustavsson et al.
Studies accounting for the fate of resi-
dues in the event they are not used for bio-
energy are consistent in concluding that an
overall reduction in GHG emissions is
achieved within the first few years of biomass
collection. Based on literature reports re-
viewed by Lamers and Junginger (2013), the
time required to achieve the reduction in to-
tal GHG emissions ranges from 0 to 16 years
from the onset of harvest residue collection
for bioenergy. A variation in the time to
overall GHG emission reduction is caused
by assumptions about the fate of residue in
the baseline scenario (e.g., decomposition
rate and rate of slash burning) and the refer-
ence fossil fuel.
The assumption that harvest residue is a
carbon “free” source of biomass for energy
because otherwise it would be burned is an
exaggeration of its fate (for example, in
AEBIOM 2013, p. 18: “the majority of the
biomass left following harvest is burned as a
waste management measure”). The reality of
the residue baseline scenario is more com-
plex. First, in some regions, all harvest resi-
due is left on site to decompose; i.e., none is
burned (e.g., McKechnie et al. 2011). De-
composition varies by region, but it is not
instantaneous. Second, even where harvest
residue is burned, a substantial fraction does
not get burned for logistical reasons (e.g.,
insufficient staffing and weather condi-
tions). Analysis of annual forest management
reports by Ter-Mikaelian et al. (2014b) re-
vealed that fewer than 50% of slash piles
were burned in northwestern Ontario, Can-
ada. Differences in slash burning rates are
also apparent among the administrative re-
gions of British Columbia, Canada (Lamers
et al. 2014). Even in the case of slash burn-
ing, the net effect of collecting it for bioen-
ergy is not zero, contrary to the suggestion
by Miner et al. (2014), because of incom-
plete combustion, with between 5 and 25%
of residue in piles remaining after burning
(e.g., Hardy 1996). Incomplete combustion
of slash when burned produces black car-
bon, which resists biological and chemical
degradation (Forbes et al. 2006). Although
the black carbon pool is relatively small, its
stability makes it an important component
of total forest carbon. Thus, the baseline for
harvest residue is not straightforward and
should reflect local conditions and practices.
Sawmill residue (sawdust and wood
chips), because it is a by-product of tradi-
tional wood products, has a substantially
lower GHG baseline scenario compared
with that of other sources of biomass because
its LCA emissions include only those from
production and transportation of biofuel
and non-CO
GHGs from its combustion.
However, according to Gronowska et al.
(2009), in the United States about 98 and
60% of primary and secondary mill residue,
respectively, is already used for energy or
other value-added products; in Canada,
70% of mill residue is currently used. Prop-
erly assessing the GHG effects of mill resi-
due used for bioenergy thus requires knowl-
edge of the existing fate of mill residue to
correctly define its baseline scenario in the
absence of use for bioenergy.
Is Forest Bioenergy “Bad” for
The aim of this review is to promote
accurate accounting of the atmospheric ef-
fects of bioenergy, not to argue against using
forest biomass for energy generation. When
correctly accounted for, GHG emissions
from live tree forest biomass used for energy
exceed those from fossil fuels for periods of a
few years to more than a century, and the
difference can be substantial, depending on
the characteristics of the forest harvested and
the fossil fuel replaced by bioenergy. Even
when bioenergy from live tree biomass from
temperate forests replaces coal, a CO
tensive fossil fuel, the time to obtain a net
reduction in atmospheric CO
can be de-
cades; if it is replacing a less CO
fossil fuel, the time to achieve an atmo-
spheric benefit may be more than 100 years.
Nevertheless, as correctly pointed out
by AEBIOM (2013) and NCASI (2013),
biomass combustion for bioenergy emits
carbon that is part of the biogenic carbon
cycle. Despite delays that may occur in
achieving a net reduction in atmospheric
carbon, as long as forests regrow, the total
amount of carbon in the biosphere-atmo-
sphere system remains approximately the
same, with small increases due to consump-
tion of fossil fuels to obtain, process, and
transport the biofuel. It is considerably more
damaging when energy is generated from
fossil fuels because this increases total carbon
in the biosphere-atmosphere system and is
essentially permanent. We also note that the
long-term GHG benefits of substituting fos-
sil fuels with forest bioenergy will greatly
surpass those of carbon sequestration in for-
ests (e.g., see Miner et al. 2014) because net
carbon accumulation in the no-harvest base-
line scenario will slow substantially as forests
reach maturity, whereas the benefits of sub-
stituting fossil fuels with forest bioenergy
will keep accumulating at a steady pace. In
addition, forest bioenergy may be needed as
a stopgap until sufficient nonfossil fuel en-
ergy generation methods, with better atmo-
spheric CO
consequences than forest bio-
mass, can be implemented. Until then, even
a century-long increase in atmospheric CO
caused by using forest bioenergy may be
preferable to burning fossil fuels. As stated
by Dehue (2013), mitigation of climate
change may not be possible without broad-
scale use of forest bioenergy; in other words,
human society is probably going to require
use of all available options to mitigate cli-
mate change, whether such options provide
a short- or long-term GHG reduction ben-
There may be reasons beyond climate
change to harvest forests to produce bioen-
ergy, such as the opportunity for forest land-
owners to receive economic benefits (as
mentioned in AEBIOM 2013), the eco-
nomic benefits to society overall of reducing
dependence on imported fossil fuels (US
Department of Energy 2013), or achieve-
ment of ecological objectives for which for-
Journal of Forestry January 2015 65
est disturbance is necessary (Colombo et al.
2012). However, the rationale for using for-
est bioenergy should avoid the false promises
of instant benefits to climate change mitiga-
tion. In this regard, we note that the princi-
ples of carbon accounting discussed in this
review should not be confused with those
described by the United Nations Frame-
work Convention on Climate Change, the
latter reflecting international carbon ac-
counting entailing political compromises
needed to reach agreement among partici-
pating parties (Prag et al. 2013).
In conclusion, some biomass sources
used for forest bioenergy may indeed pro-
vide near-immediate GHG reduction,
whereas others produce decades- to century-
long increases in atmospheric GHGs. Our
goal in this review was to support what we
consider the use of scientifically sound
knowledge for informed decisionmaking
about using forest bioenergy for climate
change mitigation and to help remove con-
fusion caused by flawed approaches to bio-
energy carbon accounting.
1. For more information, see
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68 Journal of Forestry January 2015
... Although papers use a wide variety of approaches to account for the GHG costs of forestry, they typically present their results with little discussion or explanation of the method they use (Ter-Mikaelian et al. 2015). For this paper, we reviewed more than 60 previously published studies (Appendix B) on the climate implications of forestry and wood demand. ...
... Carbon neutral means that the carbon lost from the forest and emitted to the air as wood decomposes or is burned is not counted as an emission. This is the approach followed for nearly all analyses of the carbon implications of construction timber or other LLPs (Appendix B), and the approach followed in the vast majority of papers finding GHG benefits from harvesting wood for bioenergy (see Ter-Mikaelian et al. 2015;Haberl et al. 2012). Sustainable forest management can mean many things, including just practices that allow forests to regrow, and it is often not defined. ...
... Brief comparison with alternative accounting approaches The carbon accounting approach used in this model follows the approach originated by Schlamadinger and Marland (1996) and used by numerous models since then, including those in Chen et al. (2018) and Smyth et al. (2020) as well as in papers specifically analyzing forest-based bioenergy (Bernier and Paré 2013;Manomet Center for Conservation Sciences 2010;. Accounting for the GHG costs of forestry is presently done using a wide variety of approaches, which are typically presented with little discussion (Ter-Mikaelian et al. 2015). ...
Full-text available
In this report, WRI researchers explore how rising demand for food, wood and shelter is squeezing land that’s needed for storing carbon and protecting biodiversity. This research uses new modeling to give a true global picture of the carbon opportunity costs for land use and proposes a four-pronged approach–produce, protect, reduce, restore–for sustainably managing the world’s finite land.
... The study proposes to consider in Carbon Accounting the recording of biomass residues from manufacturing, as these produce low or negative Greenhouse Gas (GHG) emissions [51,52,53], biogenic in relatively short timescales and essentially instantaneous benefits by displacing fossil fuels [54,55,56]. However, accountants should take into consideration that the benefits of forest bioenergy depend on the evaluation of forest management options [18]. Ter-Mikaelian, among others [18], highlight in their research common errors in the principles used in carbon accounting. ...
... However, accountants should take into consideration that the benefits of forest bioenergy depend on the evaluation of forest management options [18]. Ter-Mikaelian, among others [18], highlight in their research common errors in the principles used in carbon accounting. Notable among them are: Renewable equals carbon neutral; Sustained yield equals carbon neutral [57]; Diversion of traditional wood products [58]; Dividend then debt [59]; Plantations used for bioenergy have no carbon debt [60]; Abandoned plantations have no carbon debt [61]; Use of the carbon debt payment approach to carbon accounting and indirect LUC (refers to land use changes occurring elsewhere as a consequence of harvesting for bioenergy) [62]. ...
... This methodology allows decision-makers to assess the impacts of carbon transfer within regional forest sectors. Other elements highlighted in the research of Fain et al [45], as well as the study of Ter-Mikaelian, among others [18], propose principles involved in carbon accounting, such as: On-site Forest carbon pools; Off-site Forest carbon pools, Substitution, Carbon transfer, Leakage. On the other hand, Vanderklift et al [19], conduct research where they point out that the reduction of greenhouse gas emissions must be real, measurable, and credible. ...
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1) Background: Carbon accounting, provides society with accurate and reliable information on the production and capture of carbon, as well as its costs and revenues. Carbon accounting is also important for product quality control, safety management and environmental compliance. This systematic review aims to respond to the objective of analyzing carbon accounting as a forestall innovation, in order to support the forestry industry in the economic-financial evaluation of the reducing greenhouse gas emissions. (2) Methods: Articles were selected based on Systematic Reviews and Meta-Analyses (PRISMA). Regarding the eligibility of the reviews, the PICOS strategy (population, interventions, comparators, outcomes and study design) was used from 347 articles scientifically identified in the Web of Science Journal Citation Report databases. Eleven articles were included in the literature review phases. (3) Results: The results of the present review propose to standardize the methodology of accounting for the total amount of greenhouse gases (GHG) emitted during the life cycle of goods and services, based on Life Cycle Assessment (LCA). (4) Conclusions: Carbon accounting and its principles, models and Methodology are used to measure and value the environmental impacts and climate risks of economic activities and investments. (4) Conclusions: The principles, models and Methodology in Carbon Accounting are used individually or in combination to provide a more complete and accurate view of the management of environmental impacts and climate risks in an organization or a project. (4) Conclusions: Carbon accounting is dynamic, will improve and evolve every day, based on the environmental impact of carbon production and capture.
... There is a demand for forest bioenergy, and the biomass source used for forest bioenergy can reduce greenhouse gas emissions. However, other uses of forest biomass can potentially increase greenhouse gas emissions in the long term (Ter-Mikaelian et al., 2015). Forests act as a source of carbon emissions and a carbon sink (Mitchard, 2018). ...
... Restoring trees is currently one of the most effective strategies for mitigating climate change (Bastin et al., 2019). However, while biomass sources for forest bioenergy reduce greenhouse gas emissions, other uses of forest biomass have the potential to increase greenhouse gas emissions in the long term (Luyssaert et al., 2008;Ter-Mikaelian et al., 2015). ...
... Wood-based bioenergy is often compared favorably to fossil fuels and several renewable energies due to a relatively low amount of fossil fuel inputs and a smaller "carbon footprint" (Malmsheimer et al. 2008 being "carbon neutral" based upon the idea that any carbon that is released by the burning or use of wood for energy is recaptured through the sequestration of the forest as it regrows (Johnson 2009). The reality is more complex: The carbon effects associated with bioenergy production need to be evaluated to include the entire life cycle of energy production, as well as the longer term use and growth of the land used to produce the energy, relative to the business-as-usual use of fossil fuels (Haberl et al. 2012, McKechnie et al. 2010, Millar et al. 2012, Ter-Mikaelian et al. 2015. While many studies support the idea that woody bioenergy produced from sustainably managed forests can have carbon benefits over the long term, the degree of benefit is heavily influenced by factors that include the initial forest conditions, forest productivity, fossil energy from harvest operations and transportation, and the type of fossil fuel that is replaced by wood (Eriksson et al. 2007, Malmsheimer et al. 2008, Petersen Raymer 2006, Zanchi et al. 2012. ...
... While many studies support the idea that woody bioenergy produced from sustainably managed forests can have carbon benefits over the long term, the degree of benefit is heavily influenced by factors that include the initial forest conditions, forest productivity, fossil energy from harvest operations and transportation, and the type of fossil fuel that is replaced by wood (Eriksson et al. 2007, Malmsheimer et al. 2008, Petersen Raymer 2006, Zanchi et al. 2012. A full accounting of the greenhouse gas benefit of forest bioenergy would include comparisons of forest carbon stocks for bioenergy versus a no-bioenergy scenario, as well as a full life-cycle assessment of the emissions used to produce forest bioenergy and for the displaced fossil fuel emissions , Ter-Mikaelian et al. 2015. ...
Technical Report
Full-text available
Forest and grassland ecosystems in the United States play a critical role in the global carbon cycle, and land management activities influence their ability to absorb and sequester carbon. These ecosystems provide a critical regulating function, offsetting about 12 to 19 percent of the Nation’s annual greenhouse gas emissions. Forests and grasslands are managed for many different objectives and a variety of goods and services, including clean water, clean air, biodiversity, wood products, wildlife habitat, food, recreation, and carbon sequestration. Although carbon may be of interest in developing management plans and options, it may not be a primary management objective. The amount of carbon absorbed by, and stored within, a particular ecosystem can be affected by many factors related to land management, including land-use change, management activities, disturbance, the use of harvested wood, and climate. The long-term capacity of forest ecosystems to absorb and sequester carbon depends in large part on their health, productivity, resilience, and ability to adapt to changing conditions. This report describes the role of forest and grassland ecosystems in the carbon cycle and provides information for considering carbon as one of many objectives for land management activities.
... Consequently, existing forests will not increase carbon storage in response to increased atmospheric carbon concentrations (Beedlow et al., 2004). Forest carbon stocks are the most commonly overlooked factor in assessing forest carbon emissions (Ter-Mikaelian et al., 2015). Plants absorb a great deal of CO 2 from the atmosphere. ...
Full-text available
Although Chinese society has transformed into the digital age, carbon peaking and neutrality are still important starting points for implementing the national strategy of green and low-carbon integrated growth in the Yangtze River Delta (YRD) of China. With data from 41 cities in YRD from 2005 to 2019, this paper empirically analyzes the carbon emission reduction effects from dual perspectives of forest resource endowment and low-carbon pilot policy in the digital age. The findings include: (1) Forest resources are indeed conducive to reducing carbon emissions. However, when considering the carbon sequestration effect of forests, a nonlinear U-shaped relationship exists between forest resource abundance and net carbon emissions per GDP. (2) Low-carbon city pilot policies are effective in reducing carbon emissions. (3) Low-carbon pilot policies perform better in smart cities, resource-based cities, and cities with abundant forest resources, showing significant heterogeneity. Forests can be relied on to assist in carbon emission reduction in the short term, but in the long term, a forest ecosystem with biodiversity is needed to achieve low-carbon sustainable development. This article provides some experience and references for building green and carbon-neutral cities for YRD in the digital age.
... These forms of accounting do not accurately capture the effects of new forest harvests for the basic reason that the forest growth and regrowth used to offset the effects of new harvests would happen anyway 20 . As hundreds of scientists in letters and many scientific bodies have written, any growth or regrowth of forests that would occur anyway cannot logically alter the climate consequences of new harvests [21][22][23][24] . ...
Full-text available
After agriculture, wood harvest is the human activity that has most reduced the storage of carbon in vegetation and soils1,2. Although felled wood releases carbon to the atmosphere in various steps, the fact that growing trees absorb carbon has led to different carbon-accounting approaches for wood use, producing widely varying estimates of carbon costs. Many approaches give the impression of low, zero or even negative greenhouse gas emissions from wood harvests because, in different ways, they offset carbon losses from new harvests with carbon sequestration from growth of broad forest areas3,4. Attributing this sequestration to new harvests is inappropriate because this other forest growth would occur regardless of new harvests and typically results from agricultural abandonment, recovery from previous harvests and climate change itself. Nevertheless some papers count gross emissions annually, which assigns no value to the capacity of newly harvested forests to regrow and approach the carbon stocks of unharvested forests. Here we present results of a new model that uses time discounting to estimate the present and future carbon costs of global wood harvests under different scenarios. We find that forest harvests between 2010 and 2050 will probably have annualized carbon costs of 3.5–4.2 Gt CO2e yr⁻¹, which approach common estimates of annual emissions from land-use change due to agricultural expansion. Our study suggests an underappreciated option to address climate change by reducing these costs.
... According to this approach, high market prices for biomass, or anticipated high prices in the near future, can increase forest owner investment and improve forest management. Improvement of forest management can mean new plantings, the use of more rapidly growing seedlings, the intensification of management to increase quality and quantity of feedstock, and expansion of forests (Sedjo 2013, Ter-Mikaelian et al. 2015, Cowie et al. 2017, Nabuurs et al. 2017. In that case, these positive effects should be included in the BAU scenario. ...
Full-text available
The exploitation of forest biomass for bioenergy is commonly perceived as part of a broad strategy for climate change mitigation due to the view that forest biomass is carbon neutral. The aims of this study are to distinguish the most widely used definition of carbon neutrality and to identify the most frequently discussed aspects of the concept of carbon neutrality. This research is conducted in the form of a scoping review. The results of the scoping review demonstrated that there is no generally accepted definition of carbon neutrality. Eight main concepts of carbon neutrality were identified. The most frequently discussed aspects of the carbon neutrality concept were temporal and spatial boundaries, scenario-based assumptions, and the source of biomass feedstock. This research provides a comprehensive summary of the concept of carbon neutrality and contributes to the debate regarding forest biomass exploitation for bioenergy.
Full-text available
Woody biomass is suggested as a substitute for fossil fuels to achieve sustainable development. However, transitioning the land purpose to produce woody biomass entails investment and a tradeoff between wood pellet production and the current utilities created by the land, hindering the willingness of private landowners. To many forest landowners, forest trees and residues considered unprofitable to transport would be left in the forest without other proper use. The wasted woody resources on the land can be a potential source to increase the woody biomass supply. To support the policymakers, logging companies, state agencies, and landowners to better capitalize on these wasted resources, we aimed to identify the characteristics of woody-resource-wasting landowners and examine how to increase their likelihood to contribute to woody-biomass-based energy. By employing Bayesian Mindsponge Framework (BMF) analytics on a dataset of 707 private landowners in the United States (US), we discovered that landowners being male, having higher income, and being a member of a state/national forestry organization were more likely to waste woody resources. Moreover, woody-resource-wasting landowners perceiving woody-biomass-based energy as a substitution for fossil fuel were more likely to sell wood. In contrast, those perceiving environmental costs over the benefits of woody-biomass-based energy were less likely to sell. These findings can be used as insights for policymakers, logging companies, and state agencies to find an additional supply of woody-biomass-based energy from landowners likely to waste woody resources.
Whether the use of industrial wood pellets for bioenergy is part of the problem of climate change or part of the solution to climate change has been heavily debated in the academic and political arena. The uncertainty around this topic is impeded by contradicting scientific assessments of carbon impacts of wood pellet use. Spatially explicit quantification of the potential carbon impacts of increased industrial wood pellet demand, including both indirect market and land-use change effects, is required to understand potential negative impacts on carbon stored in the landscape. Studies that meet these requirements are scarce. This study assesses the impact of increased wood pellet demand on carbon stocks in the landscape in the Southern US spatially explicitly and includes the effects of demand for other wood products and land-use types. The analysis is based on IPCC calculations and highly detailed survey-based biomass data for different forest types. We compare a trend of increased wood pellet demand between 2010 and 2030 with a stable trend in wood pellet demand after 2010, thereby quantifying the impact of increased wood pellet demand on carbon stocks in the landscape. This study shows that modest increases in wood pellets demand (from 0.5 Mt in 2010 to 12.1 Mt in 2030), compared to a scenario without increase in wood pellet demand (stable demand at 0.5 Mt), may result in carbon stock gains of 103-229 Mt in the landscape in the Southern US. These carbon stock increases occur due to a reduction in natural forest loss and an increase in pine plantation area compared to a stable-demand scenario. Projected carbon impacts of changes in wood pellet demand were smaller than carbon effects of trends in the timber market. We introduce a new methodological framework to include both indirect market and land-use change effects into carbon calculations in the landscape.
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This review on research on life cycle carbon accounting examines the complexities in accounting for carbon emissions given the many different ways that wood is used. Recent objectives to increase the use of renewable fuels have raised policy questions, with respect to the sustainability of managing our forests as well as the impacts of how best to use wood from our forests. There has been general support for the benefits of sustainably managing forests for carbon mitigation as expressed by the Intergovernmental Panel on Climate Change in 2007. However, there are many integrated carbon pools involved, which have led to conflicting implications for best practices and policy. In particular, sustainable management of forests for products produces substantially different impacts than a focus on a single stand or on specific carbon pools with each contributing to different policy implications. In this article, we review many recent research findings on carbon impacts across all stages of processing from cradle-to-grave, based on life cycle accounting, which is necessary to understand the carbon interactions across many different carbon pools. The focus is on where findings are robust and where uncertainties may be large enough to question key assumptions that impact carbon in the forest and its many uses. Many opportunities for reducing carbon emissions are identified along with unintended consequences of proposed policies.
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Four research-based insights are essential to understanding forest bioenergy and “carbon debts.” (1) As long as wood-producing land remains in forest, long-lived wood products and forest bioenergy reduce fossil fuel use and long-term carbon emission impacts. (2) Increased demand for wood can trigger investments that increase forest area and forest productivity and reduce carbon impacts associated with increased harvesting. (3) The carbon debt concept emphasizes short-term concerns about biogenic CO2 emissions, although it is long-term cumulative CO2 emissions that are correlated with projected peak global temperature, and these cumulative emissions are reduced by substituting forest bioenergy for fossil fuels. (4) Considering forest growth, investment responses, and the radiative forcing of biogenic CO2 over a 100-year time horizon (as used for other greenhouse gases), the increased use of forest-derived materials most likely to be used for bioenergy in the United States results in low net greenhouse gas emissions, especially compared with those for fossil fuels.
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Wood bioenergy is touted as carbon neutral because biological regrowth recaptures the carbon released in energy production. However, some argue that using wood as an energy feedstock will result in decreased forest stocks and thereby a net reduction of carbon sequestered by forests. Such arguments fail to recognize that increased demand for wood bioenergy could increase stocks of wood, a renewable resource. We address the carbon neutrality question using a dynamic optimization forest management model to examine the effect of increasing or decreasing wood bioenergy demand on an existing forest, both in the amount of carbon lost by harvests and in that captured by forest management adjustments that change forest stocks under various wood demand and land supply scenarios. The results suggest for a managed regulated forest using foresight, an anticipated substantial increase in future wood biomass demand will not reduce forest and forest carbon stocks, but rather will increase the forest and forest carbon, thus being somewhat self-regulating.
Creating new coal to recycle the carbon released from coal combustion takes eons. As we have clearly shown above, with sustainable forest management, the recycling of carbon from wood combustion is contemporary and continuous. Therefore, the net stock of CO2 in the atmosphere from the combustion of wood is not increased. This conclusion underpins the policies that are both mitigating CO2 emissions and benefiting the U.S. export market. Over the next three or four years, around $3 billion will be invested in the United States for 15 million tons per year of new pellet manufacturing capacity. Annual revenues from the export of U.S. pellets are expected to be more than $2.9 billion in 2017. All of that investment is for the export of low carbon fuels to nations that have codified the carbon benefits of sustainably sourced wood pellet fuel. It is ironic that the United States, which has no policy on CO2 emissions, is the global leader in the production of low-carbon fuel for power generation in Europe.
Guidelines in the form of a six-step approach are provided for estimating volumes, oven-dry mass, consumption, and particulate matter emissions for piled logging debris. Seven stylized pile shapes and their associated geometric volume formulae are used to estimate gross pile volumes. The gross volumes are then reduced to net wood volume by applying an appropriate wood-to-pile volume packing ratio. Next, the oven-dry mass of the pile is determined by using the wood density, or a weighted-average of two wood densities, for any of 14 tree species commonly piled and burned in the Western United States. Finally, the percentage of biomass consumed is multiplied by an appropriate emission factor to determine the mass of PM, PM10, and PM2.5 produced from the burned pile. These estimates can be extended to represent multiple piles, or multiple groups of similar piles, to estimate the particulate emissions from an entire burn project.
A general model is developed to relate average carbon storage over the lifetime of a forest managed for sustained yield to the maximum biomass of the same forest at maturity. If a forest is managed for maximum sustained yield of biomass, mean lifetime carbon storage is about one-third that at maturity. When accumulation and decomposition of detritus after harvest are added, the fraction is about 0.5 in temperate deciduous forests, less in the tropics, and more in boreal forests. Harvest at financial maturity, by shortening the rotation, disproportionately reduces lifetime carbon storage, to perhaps 0.2 of the maximum. Nontimber values may affect carbon storage either positively or negatively. Forest regrowth and multispecies agricultural systems that include trees may account for more carbon storage in the tropics than is sometimes assumed.- Author
An increase in the demand for wood for energy, including liquid fuels, bioelectricity, and pellets, has the potential to affect traditional wood users, forestland uses, management intensities, and, ultimately, carbon sequestration. Recent studies have shown that increases in bioenergy harvests could lead to displacement of traditional wood-using industries in the short run and intensive management, land use change, and sawtimber market impacts in the long-run. We simulate timber markets, as well as land use response and carbon outcomes resulting from projections of both traditional and bioenergy wood use in Alabama, Georgia, and Florida under differing levels of market supply responses. Increased logging residue recovery had a moderating effect on prices, although increased planting response led to higher carbon sequestration, and smaller effects on prices. Increased forest productivity led to lower prices, but also led to reduced timberland and thus lower forest carbon sequestration. Supply responses will be crucial to moderating market responses to increases in bioenergy wood demands.