Daniel Kneeshaw, September 18th, 2019

 "When drought is beneficial for forests and other lessons from climate change research in Canada"


There is much uncertainty around the influence of climate change on forest growth. Longer growing seasons could lead to increased growth but extreme events such as drought and heat are expected to cause declines in productivity and greater mortality of the most vulnerable species. We’ve used greenhouse experiments, longterm observations and over 50 000 tree cores to investigate these effects.   Our research suggests that seasonal timing of growth may be more important than stomatal control on species drought tolerance. Site characteristics were also found to be more important drivers of tree vulnerability to drought than tree species leading us to question the degree to which foresters should  invest in species selection to increase forest resilience to climate change. We also observed that although drought and heat stress cause growth reductions in southern Canada, warming and drying leads to increased growth. Beneficial effects may, however, only occur for a few decades before reversing requiring  foresters  to continuously adapt practices.


Daniel Kneeshaw (Centre for forest research, UQAM) and a former chief editor of the Canadian Journal of Forest Research is a researcher in in forest ecology interested by the influence of natural disturbances (insect oubreaks, fires, windthrows) and climate change (warming and drying) on the growth and survival of our forests.  He is currently leading a project to instrument monitoring sites across Canada as well as teams studying the effects of droughts and insect outbreaks on forest dynamics. His work focuses on improving forest management techniques to lead to more resilient forests.