Drought type determines the pattern of ecological response to drought in trees with different sensitivities

Abstract

Aims

The increase in the frequency, magnitude and duration of drought events resulting from climate warming is modifying global tree growth distribution patterns and ecological functions, while also impairing trees' capacity to withstand water stress. However, the underlying ecological response mechanisms of trees to various types of droughts remain unclear.

Methods

We delineated the spatial distribution of tree drought sensitivity. Additionally, we examined the response characteristics towards atmospheric drought, soil drought, and compound drought for tree growth with different sensitivities, along with identifying key drivers influencing changes in tree resilience.

Results

The findings revealed that: 1) Drought suppression trees showed greater vulnerability and the highest growth reduction, while drought promoting trees had better resistance and the shortest recovery period. 2) Variations were observed in the response patterns of trees towards different types of droughts, showing that soil and compound drought exerted more constraints on tree growth with the greater variability in resilience compared to atmospheric drought. 3) The resilience indices change had latitude pattern and was controlled by humidity condition before and after drought. With the improvement of water conditions before and after drought, drought resistance and recovery of drought suppression trees became worse and stronger respectively. The resilience indices change pattern of drought promoting type was quite the opposite. The study enhances our understanding of the tree ecological responses mechanisms to diverse forms of drought based on their varying levels of sensitivity, which is helpful for targeted measures to severe drought events for maintaining forest health and sustainable development under climate warming.