Wildfire severity and vegetation recovery drive post‐fire evapotranspiration in a southwestern pine‐oak forest, Arizona, USA

Abstract

Abstract Post‐fire stand water balance is a critical factor influencing tree regeneration and survival, which are often modulated by fire severity. We examined influences of the post‐fire vegetation matrix and fire severity on diurnal, seasonal, and multi‐year variation in evapotranspiration (ET) by analyzing the relationship between post‐fire vegetation and ECOsystem Spaceborne Thermal Radiometer Experiment on the International Space Station (ECOSTRESS) ET data using multivariate and linear mixed effects modeling. Unlike many high‐severity fire sites where ET drops after burning, post‐fire ET was high at shrubland sites that burned at high fire severity in southern Arizona, USA. In this study, post‐fire ET was driven by plant species composition and tree canopy cover. ET was significantly higher in the morning and midday in densely vegetated post‐fire shrublands than pine‐dominated forests that remained 5–7 years after wildfire. Our results demonstrate that plant functional traits such as resprouting and desiccation tolerance drive post‐fire ET patterns, and they are likely to continue to play critical roles in shaping post‐fire plant communities and forest water cycling under future environmental change.

Keywords

• ECOSTRESS
• evapotranspiration
• high‐severity wildfire
• pine‐oak forests
• plant water balance
• post‐fire shrublands