Trees as indicators of past climates and forest dynamics in Central Canada

研究重点是环境因素（如气候、虫、病、火）如何影响树木生长和年轮形成。在加拿大，树木每年都会产生年轮，通常可以活上好几个世纪。因此，我们可以利用它们或它们的树轮特征来重建仪器记录之前的条件。例如，这种能力使我们能够在欧洲人定居之前获得气候变化的信息。然而，要做到这一点，我们需要清楚地了解当今的环境条件如何影响不同物种和栖息地的树木生长。这项研究从研究木材解剖到量化昆虫爆发、森林火灾和极端气候等大规模现象的影响。树木年轮研究不仅可以更好地了解树木的生长情况，还可以预测人类活动和/或自然变化带来的未来环境变化如何影响加拿大人及其环境。本研究主要集中在加拿大中部。首先，我们将研究树木年轮异常（例如，假年轮，霜轮）和触发它们形成的因素（例如，昆虫，疾病，干旱，温度）。我们的研究中出现的一个问题是，为什么特定区域的树木不是都记录了特定的事件？例如，是什么让一棵树成为干旱的良好记录者，而另一棵树却不是？其次，研究温尼伯湖水文变化对岸线落叶乔木生长和木材解剖的影响。第三，我们正在为马尼托巴开发的杰克松年轮年表网络将完成，并将继续用于重建昆虫爆发和气候变化等动态过程。四是推进千年森林火灾重建。这个项目包括量化和分析过去几千年来沉积在湖泊沉积物中的木炭颗粒，这些颗粒是由森林火灾产生的。第五，我们将把我们的研究扩展到湿地，特别是泥炭地的云杉生长。尽管泥炭地在加拿大和全世界都有大量的云杉，但泥炭地的科学家很少考虑到泥炭地的云杉生长。我们感兴趣的是树木为长期了解水文气候变化提供的潜力。总之，这项研究将使我们能够更好地了解树木的生长情况，更好地了解北美内陆地区气候和其他环境因素过去和现在的变化情况。鉴于我们的研究是实验室密集型的，它确实为本科生和研究生提供了许多培训和就业机会。所产生的生态信息也将有助于森林管理者（例如，加拿大公园，林业部门），因为我们的研究有助于更好地管理这些生态系统。

The research focuses on how environmental factors (e.g., climate, insect, disease, fire) affect tree growth and tree-ring formation. In Canada, trees produce annual tree rings and often live for many centuries. We can thus utilize them or their tree-ring characteristics to reconstruct conditions prior to recording by instruments. This capability allows us for example to gain information on climate variability prior to European settlement. To do so however, we need a clear understanding of how today's environmental conditions affect tree growth in various species and habitats. This research goes from studying wood anatomy to the quantification of the impact of large scale phenomena like insect outbreaks, forest fires, and climate extremes. Tree-ring research not only allows for a better understanding of growth but it also allows to foresee how future environmental changes brought by human activities and/or natural variations may impact Canadians and their environment. This research mainly focuses on central Canada. First, we will study tree-ring anomalies (e.g., false rings, frost rings) and the factors (e.g., insect, disease, drought, temperature) that trigger their formation. One of the questions arising from our research is why are trees in a given area not all recording a specific event? For example, what makes a tree a good recorder of drought and not another? Second, we intend to study the impacts of Lake Winnipeg hydrological changes on growth and wood anatomy of shoreline deciduous trees species. Third, the jack pine network of tree-ring chronologies that we are developing for Manitoba will be completed and will continue to be used to reconstruct dynamical processes like insect outbreaks and climate variability. Fourth, we will pursue our millennia forest fire reconstruction. This project involves to quantify and analyze the charcoal particles that were deposited in lake sediments over the last few millennia and that were produced by forest fires. Fifth, we will expand our research to wetlands and in particular to back spruce growth in peatland a habitat that has been little considered by tree-ring scientists despite their abundance in Canada and worldwide. We are interested in the potential that trees offers for long-term understanding of hydroclimatic changes. In conclusion, this research will allow to better understand tree growth and to better visualize the past and current variability in climate and other environmental factors in Interior North America. Given that our research is laboratory intensive, it does benefit both undergraduate and graduate students by providing many training and employment opportunities. The ecological information generated will also be helpful to forest managers (e.g., Parks Canada, Forestry Branch) as our research contributes to better manage these ecosystems.