Climate Change Impacts on Boreal Tree Function: Implications for Carbon and Water Fluxes

气候变化已经影响到加拿大的北方森林，通过减少生长和大规模死亡事件，减少了炎热干燥年份的碳吸收和封存。由于这些森林中储存了大量的碳，而且它们的地理跨度很广，因此即使是北方碳循环或物种组成的相对较小的变化也会对气候产生全球影响，其中许多变化会进一步加速高纬度气候变暖。我的研究项目侧重于了解加拿大主要的北方树种如何应对升高的温度，高浓度的二氧化碳和水资源压力，以确定近期森林衰退的潜在机制。在接下来的五年里，我的实验室将专注于评估这些气候变化因素如何改变光合作用、呼吸作用、水运和耐旱性在经济上和生态上重要的加拿大北方树种，以及如何适应这些生理性状影响树木的生长和生存。然后，我将使用基于过程的模型，利用这些机械数据来预测在未来各种气候情景下，森林生产力和对干旱和高温压力的脆弱性将如何变化。我在了解功能树对全球变化环境因素的反应方面的工作已经在一流期刊上发表了高质量的研究成果。拟议的工作将为预测加拿大森林将如何应对气候变化提供关键信息，以改进森林管理计划和减缓气候变化战略。这笔经费将允许我直接支持培训5名研究生和6名本科生暑期研究员，以及15名本科生志愿者，研究直接影响加拿大经济和环境的林业和应激生理学相关问题。

Climate change is already affecting Canada's boreal forest, reducing carbon uptake and sequestration during hot, dry years through reduced growth and large-scale mortality events. Because of the vast amount of stored carbon in these forests and their extensive geographic span, even relatively small changes in boreal carbon cycling or species composition can have global impacts on climate, many of which can further accelerate high latitude climate warming. My research program focuses on understanding how Canada's major boreal tree species respond to elevated temperatures, high CO2 concentrations and water stress, to determine the mechanisms underlying recent forest decline. Over the next five years, my lab will focus on assessing how these climate change factors alter photosynthesis, respiration, water transport, and drought tolerance in economically and ecologically important Canadian boreal tree species, as well as how acclimation of these physiological traits affects tree growth and survival. I will then use process-based models that take this mechanistic data and use it to predict how forest productivity and vulnerability to drought and heat stress will change under various future climate scenarios. My work on understanding functional tree responses to global change environmental factors has already led to a strong record of publishing high-quality research in premier journals. The proposed work will provide crucial information for predicting how Canada's forests will respond to climate change to improve forest management plans and climate change mitigation strategies. This grant will allow me to directly support the training of five graduate students and six undergraduate summer researchers, as well as fifteen undergraduate student volunteers, in pressing forestry and stress physiology-related issues that directly impact Canada's economy and environment.