Evaluating variation in the sensitivity of tree growth, mortality, and biomass allocation to climate-induced moisture stress across the western boreal forest

从马尼托巴到育空地区，加拿大西部的北方森林地区是一个全球重要的碳库。然而，近几十年来干旱的增加造成了整个区域的森林碳损失，因为水分胁迫降低了生产力（树木生长减缓），增加了死亡率。这些变化构成了重大威胁，因为气温升高和干旱加剧了火灾的风险，使树木容易受到虫害的袭击，减少了可销售木材的供应，并在碳储存释放到大气中时引发破坏性的气候变化反馈。为了更好地了解这一森林地区的气候敏感性，我们的合作伙伴关系将建立并反复调查加拿大西部三个主要北方生态区的400个地点。我们将使用地面图，无人机图像和地面激光扫描的数据（1）评估气候水的可用性对个体树木的生长和生存的影响如何在物种之间变化，与当地的竞争，并与网站水文;和（2）研究气候水的可用性和当地的竞争如何影响树冠内和地上生物量的异速生长模型中的生长分配。这项研究将使人们更清楚地了解加拿大一个主要森林地区的森林和碳动态，目前该地区的数据有限。为确保主要利益相关者广泛采用结果，我们将根据我们的发现开发一个免费提供的气候风险绘图工具。这一工具将使林业的最终用户能够评估某一特定关注地区的森林林分和碳储存对未来干旱的脆弱性。深入了解森林对区域气候压力的敏感性如何变化，是在加拿大西部森林部门制定和部署气候适应和减缓战略的关键一步。

Stretching from Manitoba to the Yukon, Canada's western boreal forest region represents a globally significant carbon pool. However, increases in aridity in recent decades have caused region-wide losses of forest carbon as moisture stress has both reduced productivity (slowed tree growth) and increased mortality. These changes pose a significant threat as warming temperatures and greater aridity together exacerbate the risk of fire, predispose trees to attack by insect pests, reduce supplies of merchantable timber, and trigger damaging climate change feedbacks when carbon stocks are released to the atmosphere. To better understand the climate sensitivity of this forest region, our partnership will establish and repeatedly survey a network of 400 sites across three major boreal ecozones in western Canada. We will use data from ground plots, unmanned aerial vehicle imagery, and terrestrial laser scanning to (1) evaluate how the effects of climatic water availability on the growth and survival of individual trees vary among species, with local competition, and with site hydrology; and (2) examine how climatic water availability and local competition influence partitioning of growth within crowns and in allometric models for aboveground biomass. This research will provide a clearer understanding of forest and carbon dynamics across a major Canadian forest region for which there is currently limited data. To ensure results are widely taken up by key stakeholders, we will develop a freely-available climate risk mapping tool based on our findings. This tool will allow end-users in the forest industry to assess the vulnerability of forest stands and carbon stocks to future drought across a given area of interest. A thorough understanding of how forests vary in their susceptibility to regional climate stress represents a critical step towards the development and deployment of climate adaptation and mitigation strategies across western Canada's forest sector.