Impacts of climate change, extreme weather events and management activities on managed conifer and deciduous forests

森林为社会提供了众多的环境、生态、社会和经济效益。加拿大东部和美国的很大一部分森林是不同树龄的人工林或管理林，它们吸收大气二氧化碳(CO2)以抵消部分化石燃料的排放。在过去的几十年里，由于过去的收获、农业废弃和植树造林的恢复，这些森林一直是一个巨大的碳(C)汇。然而，最近的研究表明，它们正受到区域气候变化和干旱、洪水和热浪等极端天气事件的影响。气候变暖加速了水文循环。森林水文循环的变化改变了森林的生长和土壤和植物的养分循环，从而反馈了碳、水循环和区域气候。迫切需要确定环境变化对森林生态系统中碳、水和养分循环的影响，特别是在不同年龄的人工林和管理林中，以充分了解它们的功能和对未来气候变化和极端天气事件的反应。我们已经建立了四个通量塔站点，包括三个针叶树龄序列(75年、40年、12年)造林林和一个管理落叶林(&gt；80年)林。*这项建议将调查森林水文和养分循环的变化对三种不同年龄的针叶林和一种落叶林固碳潜力的影响，以及这些森林将如何应对未来的气候变化和极端天气事件。它还将侧重于进一步发展陆地生态系统和水文模型(例如，加拿大地球系统模型中使用的C和N耦合的加拿大陆地表面计划-加拿大陆地生态系统模型(CLASS-CTEM+N)和一个区域水文模型(Mike-SHE)，以探索森林生态系统中的生物物理、生物地球化学和水文反馈。这些生态系统和水文模型将结合长期涡旋协方差通量和区域水文数据，以探讨气候变化和极端天气影响。该提案还将使用CTEM+N类生成的针对政府间气候变化专门委员会(IPCC，AR5)各种气候变化情景的森林生长估计，调查加拿大各地针叶林的经济吸引力和与碳封存相关的好处。量化管理森林对气候变化的反应将有助于环境规划者为其生长和生存制定适应战略。在加拿大地球系统模式中实施CLASS-CTEM+N模式将提供一种评估工具，为联邦政府和气专委制定政策生成未来气候情景，并帮助加拿大履行其国际义务。**

Forests provide numerous environmental, ecological, social and economic benefits to society. A large portion of forests in eastern Canada and US are plantation or managed forests of different ages that absorb atmospheric carbon dioxide (CO2) to offset some of the fossil fuel emissions. These forests have been a large carbon (C) sink over the last many decades due to recovery from past harvesting, agricultural abandonment and afforestation. However, recent studies indicate that they are being affected by changes in regional climate and extreme weather events such as drought, floods and heat waves. Climate warming has accelerated the hydrological cycle. Changes in forest hydrological cycle alter its growth and soil and plant nutrient cycling, which feeds-back on both carbon and water cycles and regional climate. There is an urgent need to determine the impact of environmental changes on carbon, water and nutrient cycling in forest ecosystems --in particular in different-age plantation and managed stands to fully understand their functioning and response to future climate change and extreme weather events. We have established four flux tower sites, including three conifer age-sequence (75, 40, 12 year old) afforested stands and a managed deciduous (>80 year old) stand. All four stands are located in Long Point Region Conservation Authority watershed.***This proposal will investigate the impact of changes in forest hydrology and nutrient cycling on the carbon sequestration potential of three different-age conifer stands and a deciduous forest and how these forests will respond to future climate change and extreme weather events. It will also focus on to further develop terrestrial ecosystem and hydrological models (e.g. C and N coupled Canadian Land Surface Scheme - Canadian Terrestrial Ecosystem Model (CLASS-CTEM+N) used in Canadian Earth System Model and a regional hydrological model (MIKE-SHE) to explore the biophysical, biogeochemical and hydrological feedbacks in forest ecosystems. Long-term eddy covariance fluxes and regional hydrological data will be combined in these ecosystem and hydrological models to explore climate change and extreme weather impacts. This Proposal will also investigate the economic attractiveness and carbon sequestration related benefits of conifer afforestation across Canada using CLASS-CTEM+N generated forest growth estimates for various Intergovernmental Panel on Climate Change (IPCC, AR5) climate change scenarios. Quantification of the responses of managed forests to climate changes will help environmental planners to develop adaptation strategies for their growth and survival. Implementation of CLASS-CTEM+N model in Canadian Earth System Model will provide an assessment tool to generate scenarios of future climate for policy development by the Federal Government and IPCC and help Canada meet its international obligations.**