Unravelling the effects of climate, composition and disturbance on forest productivity in the eastern boreal forest

不断变化的气候，干扰制度及其相互作用正在改变生态系统动态，特别是在高纬度森林，我的长期目标是评估几十年的增长，人口和群落动态的优势树种在整个东部北方大面积的变化。 具体来说，我将结合联合收割机的生长模式，来自全省范围内收集的树木年轮核心，研究气候敏感性的北方树木生长跨越大的环境梯度。 我们将调查两个物种和网站内的物种反应水平。另一个短期目标是评价这些相同物种在沿着东西（降水）和南北（温度）梯度上的种群（死亡率与补充率）和群落（组成的变化）动态的长期变化。由于昆虫是外温动物，它们也应该对变暖作出强烈反应，并可能与水分胁迫相互作用，使树木死亡率增加。随着云杉芽虫（一种爆发性昆虫）的范围扩大，在其传统范围内罕见的物种混合将受到越来越多的攻击。 联想关系的影响在不同的北方树种混合中，抗性增加与敏感性增加的关系将被用作北方森林系统在不同空间尺度上对非生物（气候）和生物（昆虫）胁迫的恢复力的代表。我和我的研究生们将联合收割机把从全省各地收集的365000多个树木核心的大型数据库与系统拍摄的一系列航空照片结合起来每十年一次我们还将使用落叶和物种混合的数据，从永久性的样本地块建立在目前的云杉芽虫爆发的开始。结合过去70年的地貌数据库和气候数据，我们将评估气候对每个物种的生长和种群动态的影响，结合树木变化的时空分析，将使我们能够更好地解释最近气候变化对森林组成和生产力的影响，然后预测未来的变化。 通过探索在大的时间和尺度上的多个树种的物种反应，这项工作也将使我们进一步了解物种与物种内的站点水平的树木对气候变化的反应的变化。目前大多数方法一次评估一个响应变量（即生长或死亡率）。 对真实的森林采取多管齐下的办法，将使我们能够更充分地评估气候变化对经历了一些最大气候变化的生态系统生产力的真实的影响。

Changing climate, disturbance regimes and their interactions are modifying ecosystem dynamics especially in high latitude forests; my long-term objective is to evaluate changes in decades of growth, population and community dynamics of the dominant tree species across a large region of the eastern boreal. Specifically, I will combine growth patterns derived from a province wide collection of tree ring cores to study climate sensitivity of the growth of boreal trees across large environmental gradients. We will investigate both species and site-level within species responses. Another short-term objective is to evaluate long-term changes in population (mortality vs recruitment) and community (changes in composition) dynamics of these same species along east-west (precipitation) and north-south (temperature) gradients. As insects are ectotherms they should also react strongly to warming and may interact with moisture stresses that predispose trees to increased mortality. With range expansion of the spruce budworm, an outbreaking insect, mixes of species that are rare in its traditional range will be increasing under attack. The effects of associational relationships (increased resistance vs susceptibility) in different mixes of boreal tree species will be used as a proxy for resilience to abiotic (climate) and biotic (insects) stresses in boreal forest systems at different spatial scales.To answer these questions, my graduate students and I will combine a large data base of more than 365 000 tree cores collected from across the province with a temporal series of aerial photos taken systematically every decade since 1945. We will also use defoliation and species mixing data from permanent sample plots established at the beginning of the current spruce budworm outbreak. Coupled with geomorphological data bases and climatic data for the last 70 years we will evaluate the effect of climate by site type on the growth and population dynamics of each speciesCombining temporal and spatial analyses of tree changes will allow us to better explain the influence of recent changes in climate on forest composition and productivity and to then predict future change. By exploring species responses over large temporal and scale scales with multiple tree species this work will also allow me to further our understanding of between species vs within species site-level variability in tree responses to climate change. Most current approaches evaluate one response variable at a time (i.e. growth, or mortality). A multi-pronged approach applied to the boreal forest will permit us to more fully evaluate the real effects of climate change on the productivity of an ecosystem that has undergone some of the largest climatic changes.