Item talk:Q160706

How Does Drought Influence Fire Severity in the Southwestern U.S.?

There is a growing realization that current warming trends may be associated with increases in the size, frequency, and severity of forest fires in the West. While rising temperatures can create drought conditions that favor severe fires, it is also possible that drought limits the ability of trees to survive a fire. During a drought, there is less water available for trees and more outbreaks of harmful insects and pathogens can occur, both of which can weaken trees. Tree mortality is one means of measuring the severity of a fire, and evidence shows that trees exposed to drought conditions for periods of 5-10 years are already more sensitive to the effects of fire – suggesting that drought could indeed increase fire severity. This project will examine the poorly understood relationship between drought, fire, and tree mortality in the Southwest. Researchers will use existing data on controlled burns, tree-ring analysis, and detailed climate data to determine how these variables interact. Understanding how drought and fire might work together to cause tree death is critical. More dead trees translates into poorer habitat for wildlife, increased soil erosion, and greater carbon emissions following fires – which could worsen warming trends. The warming experienced so far in the Southwest is small compared to expected future conditions, making this analysis critical for the success of long-term forest conservation. Identifying exactly how drought and fire interact to impact trees can help forest managers better understand and plan for the effects of fire in the future.