Climate change and water use: can increase diversity help protect forests?

点击翻译按钮获取中文摘要

This research project is strongly grounded on the needs expressed by our partners and by forest managers for predictions on the impacts of climate change on forests, and mitigation strategies to limit the expected mortality due to water stress and its effect of the productivity of Canadian forests. Indeed, the research developed in this project will contribute significantly to mitigating the impacts of some of the most important threats to Canadian forests: decreasing diversity and maladaptation of tree species from failure to migrate, combined with increasing periods of drought due to changes in climate. The main scientific objective of the project is to evaluate the often cited but poorly demonstrated hypothesis that forest diversity will buffer the negative impacts of water stress on productivity, especially mortality. This is a highly strategic hypothesis given the expected changes, and uncertainty, in precipitation from projected climate change in Canada. It will also be easily translated into adaptation strategies for both managed natural forests and tree plantations.Furthermore, we will evaluate the size of the impact that increased mortality caused by the maladaptation of trees following climate change will have on forest productivity, which is largely unknown at this time, and not accounted for at present by managers and governments.To do so, we use both an experimental approach, benefiting from our network of tree diversity experiments (IDENT), as well as an observational approach using data from permanent forest plots. The experimental approach will make use of a stable isotope (deuterium) to trace water uptake in trees, as well as remote sensing (drones) of leaf temperatures (thermal cameras) and canopy organization in space, to track water use and evapo-transpiration, in highly controlled tree diversity experiments that include water stress treatments. Observational analyses will benefit from our network of large permanent plots in Québec, as well as the Global Forest Biodiversity initiative, encompassing over 1 million forest plots across all forested biomes of the world.