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This activity includes efforts to regulate the recycling of forest biomass from fires, maintain healthy forest ecosystems, and reduce total emissions of CO2 and other GHGs.
Fire management practices vary greatly between forest ecosystems, depending on the historical or natural fire regime for the ecosystem, the current condition of the forest, and the management objectives of the landowner. In many cases, mechanical vegetative manipulation or planned prescribed fires can be utilized to maintain conditions approximating historical ranges. In some cases, where past fire suppression has resulted in fuel buildups, the ecological risk of burning-either in a prescribed or wildfire-is now so great that mechanical means of fuel removal may be a precursor to any management scheme designed to restore fire's role in the ecosystem (Neuenschwander and Sampson, 2000). Where such fuel removal is carried out, wildfire ignitions are less likely to result-and when they happen, they will often burn at lowered severities, with reduced fuel consumption, heat production, and GHG emissions. Because fire management is an integral part of forest management, it must be viewed in connection with other management practices, including harvest and wood utilization, to evaluate its full carbon flux effect.
Use and Potential
Destruction of forest biomass by burning releases large quantities of CO2 and
is estimated to create 10 percent of annual global methane emissions as well
as 10-20 percent of global N2O emissions. Thus, fire can have a significant
effect on atmospheric chemistry (IPCC, 1992). The process is well known in terms
of general effects, but it has many uncertain parameters in relation to specific
fire events because fire effects are related to fuel amounts, arrangements,
and conditions as well as weather conditions at the time of combustion-all of
which can be highly variable or unpredictable (Goldammer, 1990; Dixon and Krankina,
1993; Price et al., 1998; Neuenschwander et al., 2000).
Monitoring, Verifiability, Transparency, and Permanence
These factors are very difficult to achieve in relation to wildfires, which
are such highly stochastic events that any estimate of the effect of management
on actual changes in wildfire dynamics is likely to be speculative. Post-event
monitoring, however, has begun to provide estimates that can be used to build
predictive models (Neuenschwander and Sampson, 2000). Quantification of the
carbon stock impact can be estimated by comparing data on historical forest
fire frequency and fuel consumption with experience in a reporting period. Forecasting
can use techniques that take local weather history and use probability analysis
to predict the occurrence of future weather combinations that will support large
wildfires (Neuenschwander and Sampson, 2000). Such forecasting relies on the
assumption that future climate will not alter fire weather occurrence to a great
extent and that it will not contribute to large areas of forest die-off that
could create hazardous fuel levels; neither assumption may be fully warranted
at this time (Apps et al., 1999a).
Associated Impacts
The associated environmental impacts of this activity are difficult to generalize
because some ecosystems need fire to be sustainable. Restoring near-historical
fire regimes may be an important component of sustainable forestry but may also
require access (road construction) and other practices that may create other
environmental effects that are known to be deleterious. Wildland fire in areas
near human habitation creates major hazards to life and property, so intentional
restoration of historical fire regimes is a risky management activity that is
associated with serious social and economic considerations that often restrict
its application. Jobs and income may increase if the timber saved from fire
is used in sustainable forest harvesting. The costs of fire prevention in remote
forest regions and the risks of accidental fire escape during prescribed fires
are probably the most important reasons that this activity is not more widespread.
Relationship to IPCC Guidelines
Emissions of CO2 and other GHGs from forest fires following deforestation and
conversion to other land uses are included in the Guidelines. CO2 emissions
from fires within managed forests are not included, but non-CO2 emissions are.
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