Tree-ring research in the eastern Canadian taiga

北方森林是到目前为止加拿大最重要的生物群。北方植被对我们的工业和我们的生活方式很重要。然而，北方森林预计将迅速变暖，并经历更多火灾，从而威胁到它提供的服务。这项研究旨在利用树木年轮来了解在火灾干扰和气候变化的主导影响下加拿大东部泰加山脉的动态，并从古老的亚化石树木中重建过去的气候变化。第一个目标是重建经验的火灾间隔频率分布，以量化北美北方森林能够吸收多少火灾活动，并通过限制有害的短火灾间隔的流行来保护自己。由于气候变化预计会出现更严重的火灾天气条件，第二个目标是评估这种自我保护可能会在未来更严重的火灾中崩溃。第三个目标是使用从湖泊沉积物中取样的亚化石树木的X射线晚材密度测量，以开发覆盖北美北部针叶林完整共同时代的温度重建。这将为评估当前变暖趋势的重要性提供背景，并将是国际小组改进大规模(例如北半球)气候重建的期待已久的补充。第四个目标是量化火山作用对加拿大东部北部针叶林近千年来黑云杉生产力的负面影响。虽然树木年轮已被用来重建火山对气候的影响，但火山对树木生产力的影响尚不清楚，特别是黑云杉，它是北美北方落叶林中最重要的树种，也是地球上就现存量而言最成功的植物物种之一。最后一个目标是共享我们完整的千禧年树轮数据库，包括所有元数据。总体而言，这项研究将为预测和管理即将到来的气候变化和相关的森林轨迹贡献重要的发现和数据。

The boreal forest is by far the most important biome of Canada. Boreal vegetation is important for our industry and our way of living. However, the boreal forest is expected to warm rapidly and experience more fires, thus threatening the services it provides. This research aims to use tree-rings to understand the dynamics of the Eastern Canadian taiga under the dominant influence of fire disturbance and climate change and to reconstruct past climate change from ancient subfossil trees. The first objective is to reconstruct the empirical fire interval frequency distribution to quantify how much the North American boreal forest can absorb the fire activity and protect itself by limiting the prevalence of deleterious short fire intervals. Because more severe fire weather conditions are anticipated with climate change, the second objective is to evaluate how this self-protection may collapse due to more severe fires in the future. The third objective is to use X-ray-based latewood density measurements from subfossil trees sampled in lake sediments to develop a temperature reconstruction covering the complete Common Era in the North American boreal forest. This will provide context to evaluate the importance of the current warming trend and will be a long-awaited addition to improve large-scale (e.g. Northern hemisphere) climate reconstructions by international teams. The fourth objective is to quantify the negative impact of volcanism on black spruce productivity across the Eastern Canadian boreal forest during the last millenium. Although tree rings have been used to reconstruct the climatic impact of volcanoes, the impact of volcanoes on tree productivity is unknown, notably for black spruce, the most important tree species in the North American boreal forest and one of the most successful plant species on Earth in terms of standing biomass. The last objective is to share our complete millennial tree-ring database, including all metadata. Overall, this research will contribute important findings and data to anticipate and manage upcoming climate changes and associated forest trajectories.