Tree recovery following disturbance in the boreal forest

北方森林干扰后的树木恢复

• 批准号: 37582-2013
• 负责人: Lieffers, Victor
• 金额: $ 2.4万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=544804
• 关键词: Tree; recovery; following; disturbance; boreal

We will study the substrate, seeding and regeneration environments affecting the recruitment of trembling aspen and white spruce of boreal forests of western Canada. First we will refine our understanding of how successional stage, including stand composition and density before disturbance and type of disturbance affects the regeneration environment for trees. We will use a combination of remote sensing prior to disturbance and remote and ground sampling after disturbance to determine successional trajectories in each system. Further. we will use similar techniques to assess the recovery of intensively managed boreal forests that have been converted to pure conifer forests and then redisturbed by fire. As many of the legacy elements of these forests have been removed by herbicide applications, their natural pattern of successional development will be impeded by lack of sprouting propagules and by the presence of aggressive grasses. A third area of study will examine regeneration of aspen from seed - allowing movement of aspen into higher elevations and latitudes with climate change. The silky hairs of aspen seed allows it to move great distances by wind and even after it lands it will continue to move over the ground surface until it is lodged on its final microsite. Using both field and lab experiments, we will examine the resorting of aspen seed onto microsites of different moisture and texture, after the seed lands, in order to more accurately assess probability of seeds stopping on good microsites. Fourth, feather mosses dominate the understory in conifer-dominated boreal forests. These mosses have neither roots for water uptake nor stomata to control water loss, therefore they undergo rapid dry-down after rainfall, but they influence nitrogen cycling, tree recruitment and ecosystem processes. Using both field observations and experiments, we will assess these wet-dry cycles in relation to feather moss vigor, substrate porosity, hydraulic conductivity and N availability. Work applies to seedling establishment and modelling risk of fire for this important substrate. Four students will be trained.

我们将研究影响加拿大西部北方森林颤抖白杨和白云杉补充的基质、播种和再生环境。 首先，我们将完善对演替阶段（包括干扰前林分组成和密度以及干扰类型）如何影响树木再生环境的理解。 我们将结合使用扰动前的遥感和扰动后的远程和地面采样来确定每个系统的连续轨迹。 更远。我们将使用类似的技术来评估集约管理的北方森林的恢复情况，这些北方森林已转变为纯针叶林，然后又因火灾而重新受到干扰。 由于这些森林的许多遗留元素已被除草剂的使用去除，它们的连续发展的自然模式将因缺乏发芽繁殖体和侵略性草的存在而受到阻碍。 第三个研究领域将研究白杨从种子中的再生——允许白杨随着气候变化迁移到更高的海拔和纬度。 白杨种子的丝状毛发使其能够通过风移动很远的距离，即使在落地后，它也会继续在地面上移动，直到停留在最终的微型地点上。 通过田间和实验室实验，我们将检查白杨种子在种子落地后在不同湿度和质地的微场地上的情况，以便更准确地评估种子停在良好微场地上的概率。 第四，羽毛苔藓在以针叶树为主的北方森林的林下植物中占主导地位。 这些苔藓既没有吸收水分的根，也没有控制水分流失的气孔，因此它们在降雨后会迅速干燥，但它们会影响氮循环、树木补充和生态系统过程。 通过现场观察和实验，我们将评估这些干湿循环与羽毛苔藓活力、基质孔隙度、导水率和氮利用率的关系。 工作适用于这一重要基质的幼苗建立和火灾风险建模。 将培训四名学生。