Predicting the risk of drought mortality in trees

What is it about?

The realisation that climate change will undoubtedly bring ever more climatic extremes, including droughts, is a troubling one. To make matters worse, recent work has shown that trees are more susceptible to drought-related mortality than previously thought, and current vegetation models appear to be somewhat inadequate when it comes to predicting such mortality. Current gaps in understanding Tree mortality following drought is well documented, and is known to occur after both single and repeated droughts over the course of years. However, an actual mechanistic understanding of how these conditions cause trees to die is still lacking. There have been various physiological investigations into plants in different settings, and the authors suggest that the focus should be on synthesising the available information in order to test current models. They also propose remotely sensed data as a useful asset for identifying mortality events in the future. Making the best of current models There is certainly no lack of models which demonstrate the effects of drought stress on plants. The available models range in scale from high resolution ones that show changes in sugar transport at a cellular scale to those at a regional-scale such as Dynamic Global Vegetation Models. The issue is with using these models effectively to make predictions about drought mortality, especially given current gaps in mechanistic understanding. The authors recommend an increased focus on optimisation and probabilistic modelling approaches if going forward other researchers want to make useful predictions of tree mortality.

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