Asynchronous recovery of evaporation and transpiration following extreme snow damage in a subtropical forest

Abstract

Study region: The Ailaoshan National Nature Reserve forest is a mountainous water catchment area for the Lancang River basin and a subtropical ecological conservation area in southwest China. Study focus: The study aimed to understand how water fluxes in a subtropical forest responds to extreme weather disturbances and their recoveries in the post-damage years. We used eddy covariance data (2010–2019) to investigate the evapotranspiration (ET), transpiration (T), evaporation (E), and canopy conductance (Gc) before and after an extreme snow event in 2015. New Hydrological Insights: In the snow damage year, the leaf area index (LAI) decreased by 49 % compared to the pre-damage levels. The severe vegetation damage caused a significant decrease in ET, T, E, and Gc by 35 %, 36 %, 23 %, and 33 %, respectively, compared to the pre-damage levels. T returned to its pre-damage level in 2016, one year after the snow damage. In contrast, LAI, ET, E and Gc recovered to their pre-damage levels in 2018, four years after the initial damage. Reduced ET caused a strong positive RFET, which diminished forest evaporative cooling and resilience. Our results suggest that the delayed E recovery enables water reserves in the ecosystems to be used through T to support rapid understory vegetation growth. This mechanism plays critical in bolstering ecosystem resilience as it facilitates swift recovery following disturbances in subtropical forests.

Keywords

• Evaporative cooling
• Evapotranspiration
• Subtropical forest
• Canopy conductance
• Post-damage