The role of altered resource availability in determining taiga forest response to permafrost thaw

改变资源可用性在确定针叶林对永久冻土融化的反应中的作用

• 批准号: RGPIN-2019-05889
• 负责人: Baltzer, Jennifer
• 金额: $ 3.54万
• 依托单位: Wilfrid Laurier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=689763
• 关键词: role; altered; resource; availability; determining

Forests are critical to future global climate and boreal forests represent a third of world's forests, much of which occurs on permafrost (perennially frozen ground). However, boreal forests are changing rapidly due to faster rates of climate change at high latitudes and associated warmer air temperatures, altered precipitation regimes, longer growing seasons and, importantly, warmer and deeper seasonally-thawed soils. This could have global implications as these forests store 30-40% of terrestrial carbon. The pathways through which rapid thaw and its impacts on the soil environment affect boreal tree growth and productivity in the context of warmer, longer growing seasons are unresolved limiting our ability to predict changes relevant to high latitude land surface-atmosphere interactions. To advance our knowledge at this critical interface, my long-term goal is to identify key processes underlying the response of boreal trees to climate change thereby enhancing our ability to predict future boreal forest function. This will be achieved by: O1) Quantifying tree growth and recruitment responses to warming-induced changes in soil resources using tree ring studies and measuring signatures of the resources used (and locked into the tree rings) during those growth periods; O2) Evaluating the ability of young trees to access water and nutrients released deeper in the soil profile where permafrost thaw occurs; O3) Determining variability in leaf and root traits in response to permafrost conditions; and O4) Quantifying recent forest dynamics (growth, recruitment, death) across the permafrost gradient and in sites with and without ground ice. These studies will provide insights into the potential for trees to access novel resources released during permafrost thaw and whether this response has a limited duration, key information for predicting boreal forest function under ongoing warming and thaw.

森林对未来的全球气候至关重要，北方森林占世界森林的三分之一，其中大部分发生在永久冻土(永久冻土)上。然而，由于高纬度地区气候变化速度加快，气温变暖，降水制度改变，生长季节延长，更重要的是，季节性融化的土壤变得更温暖和更深，北方森林正在迅速变化。这可能会对全球产生影响，因为这些森林储存了30%-40%的陆地碳。在更温暖、更长的生长季背景下，快速融化及其对土壤环境的影响影响北方树木生长和生产力的途径尚未解决，限制了我们预测与高纬度陆地表面-大气相互作用相关的变化的能力。为了提高我们在这一关键界面上的知识，我的长期目标是确定北方树木对气候变化反应的关键过程，从而提高我们预测未来北方森林功能的能力。这将通过以下方式实现：O1)利用树木年轮研究和测量那些生长期所用资源(和锁定在树木年轮中)的特征，量化树木的生长和补充对气候变暖引起的土壤资源变化的反应；O2)评估幼树获得在发生冻土融化的土壤剖面中更深层释放的水和养分的能力；03)确定叶片和根系特征对多年冻土条件的反应的变异性；以及O4)量化跨永久冻土梯度和有和没有地面冰的地点最近的森林动态(生长、补充、死亡)。这些研究将深入了解树木获得在永久冻土融化期间释放的新资源的潜力，以及这种反应是否具有有限的持续时间，这是预测北方森林在持续变暖和融化下功能的关键信息。