188.8.131.52. Discrepancies between Actual and Reported Stock Changes
Although afforestation and reforestation ordinarily result in net carbon sequestration
and deforestation results in net carbon emissions, these outcomes may not always
be true in reporting under Article 3.3, depending on the definitions and carbon
accounting approaches adopted. Certain definitions of ARD could result in Parties
receiving "credits" (i.e., additions to their assigned amounts) for activities
that cumulatively result in an increase or no change in atmospheric CO2 (type
I discrepancy). Conversely, certain definitions could result in Parties receiving
debits (i.e., deductions from their assigned amounts) for activities that result
in reductions or no change in atmospheric CO2 (type II discrepancy). This section
analyzes some of these possibilities. The discussion below is organized around
the terms "forest," "reforestation," "degradation," and "deforestation":
- Forest. If forests are defined on the basis of a threshold for canopy
cover or biomass density, a certain number (e.g., 10 percent canopy cover
of trees) will be the cut-off point between forest and non-forest land. Two
type I discrepancies suggest themselves:
- Forests with canopy cover that is greater than the threshold value
could be degraded to the defined canopy cover limit, releasing a large
amount of carbon to the atmosphere or transferring it to non-forest carbon
pools, without carbon debit. Subsequent deforestation of the 10 percent
canopy cover forests could result in an accounting of carbon loss that
matches the carbon in the 10 percent canopy forest rather than in the
forest that existed previously. Only the Degradation/ Aggradation and
Biome definitional scenarios could avoid this problem-and only if the
maximum crown cover or carbon content of vegetation at maturity is reduced.
Otherwise, such degradation effects could be covered only by Article 3.4.
- Thinning or clear-cut harvesting operations on afforestation/reforestation
lands could occur just before the first commitment period and between
subsequent commitment periods to maximize carbon increments over the commitment
period. This effect could be minimized through specification of contiguous
commitment periods. Forest managers, however, are unlikely to base their
management decisions mainly on considerations of carbon credits rather
than silvicultural needs and timber market demands.
- FAO scenario. If a stand is cleared and reforested between 1990
and 2008, carbon credits could be claimed even if the carbon stocks in
the landscape are not increasing (type I discrepancy) (see Section
3.5.2). For a stand that is cleared and reforested between 2008 and
2012, we have to separate the three accounting options described in Section
- Activity-based approach. Carbon stock losses at the time
of harvest are not accounted, nor are subsequent emissions from decaying
dead organic matter. Only the accumulation of carbon in the new stand
and in new dead organic matter is accounted because it results from
the reforestation activity. Carbon credits could be claimed even if
the carbon stocks in the landscape are not increasing (type I discrepancy)
(see Section 3.5.2 for results on the landscape
- Land-based approach I. The stock change over the full commitment
period is measured, including stock losses during harvest, as well
as delayed emissions from dead organic matter. The consequence is
a large debit (except where rotation periods are below 20 years) (see
Section 3.5.2). This is a type II discrepancy.
- Land-based approach II. The carbon stock change between
the beginning of the activity and the end of the commitment period
is measured, including the decaying slash resulting from the harvest.
In the short term, debits may be reported because of the effects of
decaying slash (type II discrepancy). In the long term, credits will
accrue even if stocks on the landscape are not increasing (type I
discrepancy) (see Section 3.5.2 for results
on the landscape level).
- All definitional scenarios. Assume a case where land is deforested
and used for agriculture before 2008, then reforested. Credits could be
claimed even though carbon stocks in the commitment period are likely
to be lower than in 1990 (type I discrepancy).
- In the case of afforestation or reforestation between 1990 and 2008,
carbon stocks can decrease in a commitment period-for example, because
of harvesting or thinning. Debits would be assigned even though the afforestation
or reforestation activity reduces atmospheric CO2 in the long run and
carbon stocks in the commitment period likely exceed those in 1990 (type
- FAO scenario. There can be an unbalanced treatment of different
harvesting methods because partial cutting techniques do not result in
reforestation under this scenario. This imbalance could result in an incentive
to favor clear-cutting over other harvesting methods, possibly working
against other considerations related to sustainable forest management.
In all scenarios except Land Cover and FAO (in combination with land-based
approach I), forestry activities could focus on high carbon-density forests
because they can be harvested without carbon penalty as long as another forest
replaces them. No carbon has to be accounted when forests of high carbon density
are logged (and their large amounts of carbon released) and replaced by plantings
with low carbon stocks (type I discrepancy).
FAO and IPCC scenarios. The forest definition contains a list of exceptions
for lands that are forests without reaching the crown-cover threshold at maturity.
For example, the determination of whether a new road results in deforestation
would be based on the use of the road. If it is used to access forest stands
for logging, it would not be considered deforestation, whereas a road that
is used for transportation (such as a new highway) would be. For the purpose
of determining long-term impacts on the atmosphere, this distinction is arbitrary.