Widespread biophysical cooling effects due to post-fire greening

Xi, H. and Wang, Q. and Xiao, Y. and Guo, R. and Tong, X. and Atkinson, P.M. (2026) Widespread biophysical cooling effects due to post-fire greening. International Journal of Applied Earth Observation and Geoinformation, 147: 105211. ISSN 0303-2434

Abstract

Wildfires and greening are two important biophysical processes that influence land surface-climate feedback patterns. However, the impact of post-fire greening, which primarily reflects canopy structural recovery, on land surface temperature (LST) remains uncertain, particularly at the daily scale, as this temporal resolution allows for a clearer observation of how fire seasonality and vegetation regrowth influence short-term land surface energy dynamics. In this research, using satellite sensor observations covering the globe from 2004 to 2019, we found that the median post-fire recovery time of leaf area index (LAI) was 479.5 days. Most forests exhibited faster canopy LAI recovery than low-stature herbaceous vegetation, likely due to differences in burn severity and affected plant structures. Fire seasonality also shaped LAI recovery patterns: dry-season and spring fires led to quicker regrowth, with the shortest recovery in temperate spring fires (173.7 days), while wet-season and summer fires showed delayed recovery, especially in cold zones where summer fires need 425.5 days to recovery. During post-fire greening, the annual cycle of LAI recovery caused an average cooling effect of −0.04 K d-1, due to the strong evapotranspiration-climate negative feedback. However, seasonal effects varied: summer fires in temperate and cold zones led to cooling, with the strongest warming observed after temperate winter fires (up to 0.104 K d⁻1). Furthermore, we observed a widespread decrease in carbon use efficiency during post-fire LAI recovery, which means that the recovery rate of ecosystem carbon sinks may not be synchronized with the rate of vegetation greening. By distinguishing between structural and functional recovery, we found that early evapotranspiration-driven cooling during structural recovery may not persist throughout ecosystem functional recovery. This study enhances our understanding of the global biophysical climate effects of post-fire greening in the context of the earth’s land surface-climate feedback, and reveals precise changes in the component parts of this feedback effect.