Restore or maintain fire in fire-adapted ecosystems

Wildfires are a major contributor of U.S. forest carbon emissions, although annual emissions can vary greatly from year-to-year. Prescribed fire can reduce fuel loads, significantly reducing the risk of uncontrolled fire or shifting fire regimes from infrequent, high severity fires towards more frequent, low severity fires that result in lower carbon emissions compared to wildfire. Additionally, prescribed fires limit the extent of wildfire if one were to occur. Conditions during implementation of prescribed fire typically result in low overstory tree mortality rates, preserving both carbon in live trees and the potential to sequester future carbon through tree growth.

Natural disturbance events—including insect pests and diseases, damage from wind and ice, drought, and wildfire—typically reduce near-term forest carbon stocks while initiating long-term and gradual recovery. These disturbances are both a major causes of carbon loss in forests and influence future sequestration rates through impacts on species composition, ecosystem structure, rates of photosynthesis and respiration, and flows through various carbon pools. While forest regrowth offsets carbon losses following human and natural disturbances over time allowing U.S. forests to remain a net carbon sink, enhanced disturbance frequency, severity, or extent from climate change may enhance large-scale forest carbon release. Shifting climatic conditions, including earlier snowmelt, low precipitation, and warmer temperatures contribute to increases in fire size, frequency, and the area burned annually in the U.S.. Impacts of wildfire on forest carbon sequestration can be long lasting and profound, particularly when they occur outside of the historical fire regime. Not only do wildland fires emit carbon stored in trees that have been burned, but mineral soils and forest floor carbon stocks can also be reduced significantly. Additionally, carbon sequestration rates can be lowered in burned areas because of negative impacts on vegetation productivity following severe fire. While many actions associated with this strategy can result in a short-term, low magnitude, or fine-scale forest carbon loss, this strategy aims to avoid or reduce long-term, large magnitude, or broad-scale carbon losses through management actions intended to decrease natural disturbance frequency, extent, intensity, or severity.