Quantifying and forecasting tree mortality risks and uncertainties of Canadian boreal forests under a changing climate

气候引起的树木死亡已经成为一个全球关注的问题，根据对未来气候变化的预测，预计这种担忧将会增加。加拿大北方森林占据了加拿大总林地的77%，在地球表面反照率和全球碳收支中发挥着关键作用。最近的研究表明，由于气温上升和更严重的干旱以及云杉芽孢子虫的落叶，加拿大北方森林可能非常容易受到树木死亡率快速上升的影响。预测树木死亡率增加对碳预算的潜在影响需要地方和区域两个尺度。然而，在大规模的碳循环模拟研究中，这些影响通常被忽视，因为关于大面积树木死亡的数据收集起来成本很高，因此不能广泛获得。迫切需要建立更好的科学认识，量化和预测未来气候变化和相关昆虫干扰对加拿大北方森林生态系统的影响，包括生态系统生产力、树木死亡以及陆地和大气之间通量的时间和大小的变化。据我所知，在加拿大，还没有使用模型-数据融合(MDF)方法对树木死亡率的变化进行比较研究，MDF方法将观测到的林地和遥感数据与气候数据和基于过程的森林模型相结合。 这项为期5年的研究计划的中心目标是开发和使用最新的三重死亡率，以1)更好地了解和预测森林生长、死亡率和生物质碳；以及2)通过使用新的模型-数据融合方法量化和减少风险和不确定性，这些风险和不确定性是关于面对气候变化时树木死亡造成的森林蓄积量和生物质碳的损失。我们的方法将提供一种强大和易处理的方式，将树木死亡率纳入森林模型，以减少在不断变化的气候中加拿大北方森林生态系统命运的不确定性。目前的研究计划将集中在加拿大东部的北方森林。这项工作将填补我们在气候变化对加拿大北部森林的树木死亡、生物量和碳平衡的直接影响领域的知识空白。这项研究将为更好地量化和预测干旱和昆虫的影响以及更好地理解气候变化将如何改变21世纪的地球森林铺平道路。从这项研究中获得的知识将转移给森林管理者、行业合作伙伴和政策制定者。该探索计划将帮助培训15名高素质的人员(10名本科生、2名硕士、2名博士和1名博士后)，涉及森林生长、死亡率、遥感、气候变化和生物量/碳关系等领域。

Climate-induced tree mortality has emerged as a global concern that is expected to increase under the projections of future climate change. Canadian boreal forests, which occupy 77% of Canada's total forest land, play a critical role in the Earth's surface albedo and the global carbon budget. Recent studies suggested that Canadian boreal forests may be highly vulnerable to rapid increases in tree mortality due to warmer temperatures and more severe droughts and defoliation by spruce budworm. Forecasting the potential impacts of increasing tree mortality on carbon budgets requires both local and regional scale. These impacts, however, have generally been ignored in large-scale carbon cycle modeling studies because data on tree mortality over large areas are expensive to collect, and therefore not widely available. There is an urgent need to develop a better scientific understanding and to quantify and forecasting the impacts of future climate change and associated insect disturbances on boreal forest ecosystems in Canada, including ecosystem productivity, tree mortality and changes in the timing and magnitude of fluxes between the land and the atmosphere. To my knowledge, no comparable studies on changes in tree mortality rates have been conducted in boreal forests using a model-data fusion (MDF) approach which integrates observed forest plots and remote sensing data with climate data and a process-based forest model in Canada. The central objective of this 5 year research program is to develop and use state-of-the-art of TRIPLEX-mortality to 1) better understand and predict forest growth, mortality and biomass carbon; and 2) quantify and reduce risks and uncertainties by using new model-data fusion approach on the loss of forest growing stock and biomass carbon due to tree mortality in the face of climate change. Our approach will provide a powerful and tractable way of incorporating tree mortality into forest models to reduce uncertainty over the fate of Canadian boreal forest ecosystems in a changing climate. The present research program will focus on the boreal forests of eastern Canada. This work will fill in our knowledge gaps in the area of the direct effects of climate change on tree mortality, biomass, and carbon balance of Canada's boreal forests. This study will pave the way for better quantifying and forecasting drought and insect impacts and better understanding of how climate change will alter Earth's forests in the 21st century. The knowledge gained from this research will be transferred to forest managers, industry partners and policy makers. This Discovery program will contribute to the training of 15 highly qualified personnel (10 undergraduates, 2 MSc, 2 PhDs and 1 post-doctorate) in the areas of forest growth, mortality, remote sensing, climate change and biomass/carbon relationships.