Vegetation-fire feedback reduces projected area burned under climate change.

Area of Science:

• Ecology
• Climate Science
• Forestry

Background:

• Climate change influences vegetation and disturbance processes like wildfire.
• Fire is a self-limiting process influenced by productivity, yet fire projections often assume sufficient fuel.
• This assumption has substantial implications for carbon dynamics and emissions.

Purpose of the Study:

• To simulate forest dynamics under projected climate and wildfire in the Sierra Nevada.
• To account for climate effects on fuel flammability and the interaction of prior fires and climate on fuel availability and flammability.
• To assess the impact of these factors on projected area burned and emissions.

Main Methods:

• Simulated forest dynamics using projected climate and wildfire data for the Sierra Nevada.
• Incorporated static climate effects on fuel flammability.
• Included dynamic effects of climate and prior fires on fuel availability and flammability.

Main Results:

• Accounting for the interaction of prior fires and climate on fuel availability and flammability moderated the projected increase in area burned by 14.3%.
• This moderation reduced predicted increases in cumulative emissions by 38.3 Tg carbon dioxide (CO2) and 0.6 Tg particulate matter (PM1).
• These reductions represent 12.9% and 11.5% decreases in CO2 and PM1 emissions, respectively.

Conclusions:

• The interaction between prior fires and climate significantly moderates wildfire projections.
• Over-estimates of climate-driven increases in area burned are possible when fuel availability is not considered.
• California will likely continue to face significant wildfire and air quality challenges due to climate change.