Mixed forests management for enhancing adaptation to climate change

面对气候变化对森林和以森林为生的社区造成的前所未有的影响，迫切需要采取新的战略来加强复原力和减少气候变化的影响。研究人员和管理人员正在将注意力转向混交林，因为有证据表明，通常用于实现利润最大化的单一物种森林更容易出现健康问题，导致生产力下降。我们可以设计特定的物种混合，以提高适应的生态和经济效益-但如何？自20世纪70年代以来，许多长期的混合物种实验已经在BC安装。然而，虽然这种长期数据对于开始研究混合物是必要的，但由于缺乏精细的空间和时间数据，在了解森林如何应对干旱事件或虫害方面的真正进展受到严重限制。我的长期目标是确定在物种组成和森林结构方面的造林选择促进所需的生态系统功能。在今后五年内，12 HQP将开发和应用新的监测工具，以量化各种混合物、物种安排和立地条件如何影响：（1）林分结构，特别是光照利用和木材质量的空间互补性;（2）生物量分配、碳储存和资源利用的时间互补性;（3）对干旱、昆虫和病原体的脆弱性。为了产生最大的实际影响，拟议的工作将侧重于加拿大西部常见的物种混合物，既包括云杉与黑松混合的内陆森林，也包括道格拉斯冷杉与桤木混合的沿海森林。方法该方案将使用一种新的高度详细的空间信息的森林结构和高分辨率的时间增长和用水数据与基于过程的建模相结合。树冠和分支三维结构将使用地面激光扫描，一种非破坏性的方法，在一系列森林的立场与不同的物种混合，这已经受到了一系列的干扰类型和强度。这些数据将与树级模型结合使用，以量化对光吸收和生产力的影响。树芯和点测树仪将分别提供年度和小时分辨率的生长数据。生长数据将与用液流传感器和同位素获得的水利用效率测量相结合。影响这项研究将建立新的造林技术，旨在推动围绕种植和管理未来准备好的混合物种森林，以满足林业部门和社会的需求的决策。我的研究团队将开发新的方法来量化资源利用的互补性和对干旱，昆虫和病原体混合物的适应能力，国际研究界将使用这些方法。这项研究将吸引包括森林机构和林业在内的大量利益攸关方的参与。

Background In the face of unprecedented climate change impacts on forests and forest-dependent communities, new strategies to enhance resilience and reduce the impacts of climate change are urgently needed. Researchers and managers are turning their attention to mixed forests, as evidence shows that single- species forests, often used to maximize profit, are more prone to health problems resulting in reduced productivity. We can design specific mixtures of species to enhance ecological and economic benefits for adaptation- but how? Many long--term mixed- species experiments have been installed in BC since the 1970's. However, while such long-term data is necessary to begin to examine mixtures, true advances in understanding how forests react to drought events or insect attacks are severely limited by a lack of fine-scale spatial and temporal data. Objectives My long-term objective is to determine which silvicultural choices in species compositions and forest structures promote desired ecosystem functions. Within the next five years, 12 HQP will develop and apply novel monitoring tools to quantify how various mixtures, arrangement of species and site conditions affect:(1) Stand structure, specifically spatial complementarity in light use and wood quality;(2) Biomass allocation, carbon storage and temporal complementarity in resource use; and (3) Vulnerability to drought, insects and pathogens. To have maximum practical impact, the proposed work will focus on species mixtures that are common in western Canada, both in interior forests such as spruce mixed with lodgepole pine, and coastal forests such as Douglas-fir mixed with alder. Methods This program will use a novel combination of highly detailed spatial information of forest structure and high-resolution temporal growth and water-use data with process-based modelling. Crown and branch 3-D structure will be collected using terrestrial laser scanning, a non-destructive method, across a range of forest stands with varying species mixtures, which have been subject to a range of disturbance types and intensities. This data will be used in combination with a tree-level model to quantify the implications for light absorption and productivity. Tree cores and point dendrometers will provide growth data with yearly and hourly resolution respectively. Growth data will be coupled with water-use efficiency measurements obtained with sap-flow sensors and isotopes. Impact This research will establish novel silvicultural techniques designed to drive decisions around planting and management of future-ready mixed-species forests that meet the needs of the forest sector and society. My research team will develop new methodologies to quantify complementarity of resource use and resilience to drought, insects and pathogens in mixtures, that will be used by the international research community. This research will engage a large number of stakeholders including forest agencies and the forest industry.