Vulnerability of eastern Canadian forests to climate warming: environmental drivers, plasticity and climatic thresholds

加拿大东部森林对气候变暖的脆弱性：环境驱动因素、可塑性和气候阈值

• 批准号: RGPIN-2019-04353
• 负责人: DOrangeville, Loïc
• 金额: $ 2.4万
• 依托单位: University of New Brunswick
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714571
• 关键词: Vulnerability; eastern; Canadian; forests; climate

Given the crucial role of Canada's forest for carbon sequestration, maintenance of biodiversity and wood supply, my long-term objective is to assess the vulnerability of the Canadian forest to projected increases in temperatures and water stress and provide crucial knowledge on mitigation solutions. Over the next five years, I aim to A) determine the role of local environmental drivers on stand vulnerability to drought, B) assess the importance of local adaptation and plasticity in tree species, and C) identify species-specific climatic thresholds. To better understand the environmental drivers of drought vulnerability, we will build a new tree-growth monitoring network by setting up plots in New Brunswick, which will allow us to monitor at high-resolution the stand-level variability in tree responses to water deficits. Such results will highlight environmental drivers of drought vulnerability, thus providing crucial knowledge to better inform management strategies. In complement, we will set up a series of greenhouse experiments to determine the role of drought timing on stand vulnerability. We will compare the drought sensitivity of multiple species growth and carbon allocation under five warming levels and three timings of water deficit in a controlled environment. Amongst climate change mitigation solution, replacing native trees with trees of the same species, but from populations growing under warmer climates may improve forest tolerance to climate change. We will assess the performance of adult trees from the entire species distribution range, planted in well-designed experiments at Acadia Research Forest and compare their climate sensitivity with that of native populations. In complement, we will compare the climate sensitivity of a black spruce population planted fifty years ago along a 5C temperature gradient from northern Quebec to southern Maine. Climate sensitivity will be assessed by matching dendroanatomical characteristics of tree-rings with seasonal climate. Finally, we will expand earlier work conducted in the province of Québec to include Atlantic Canada and Maine in order to better assess current climatic thresholds of dominant tree species of Eastern Canada. We will fit generalized additive models using tree growth data from permanent sample plots across this large climate gradient. These models will allow us to simulate changes in growth according to alternative climate and management scenarios and help detect regional species declines. The impact and applications of this work consist in weighing the role of the factors (e.g. competition, species) that control future changes in eastern Canada's forest dynamics due to climate warming. This new knowledge will help inform management solutions to reduce forest vulnerability and help maintain maximum benefits and sustainability. This research program will also be instrumental in acquiring new fundamental knowledge on forest ecology and ecophysiology of wood growth.

鉴于加拿大森林在碳封存、维护生物多样性和木材供应方面的关键作用，我的长期目标是评估加拿大森林对预计气温和水压力上升的脆弱性，并提供有关缓解解决方案的关键知识。在接下来的五年里，我的目标是A）确定当地环境驱动因素对林分干旱脆弱性的作用，B）评估当地适应性和可塑性在树种中的重要性，以及C）确定物种特异性气候阈值。 为了更好地了解干旱脆弱性的环境驱动因素，我们将在新玩法建立一个新的树木生长监测网络，这将使我们能够以高分辨率监测树木对缺水反应的林分水平变异。这些结果将突出干旱脆弱性的环境驱动因素，从而为更好地指导管理战略提供关键知识。作为补充，我们将建立一系列温室实验，以确定干旱时间对林分脆弱性的作用。我们将比较干旱敏感性的多个物种的生长和碳分配下五个变暖水平和三个时间的水分亏缺在一个受控的环境。 在减缓气候变化的解决方案中，用同一物种的树木取代本地树木，但从温暖气候下生长的种群可以提高森林对气候变化的耐受性。我们将评估整个物种分布范围内的成年树木的表现，这些树木种植在Arabidia研究森林的精心设计的实验中，并将它们的气候敏感性与本地种群进行比较。作为补充，我们将比较50年前从魁北克北方到缅因州南部沿着5 ℃温度梯度种植的黑云杉种群的气候敏感性。气候敏感性将通过将树木年轮的树木解剖学特征与季节性气候相匹配来评估。 最后，我们将扩大魁北克省进行的早期工作，包括大西洋加拿大和缅因州，以更好地评估目前的气候阈值的主要树种加拿大东部。我们将使用来自这个大气候梯度的永久样本地块的树木生长数据拟合广义加性模型。这些模型将使我们能够根据替代气候和管理情景模拟生长变化，并帮助检测区域物种减少。 这项工作的影响和应用包括在权衡的作用的因素（如竞争，物种），控制未来的变化，加拿大东部的森林动态，由于气候变暖。这一新知识将有助于为减少森林脆弱性的管理解决方案提供信息，并有助于保持最大效益和可持续性。这项研究计划也将有助于获得森林生态学和木材生长的生态生理学的新的基础知识。