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

森林为社会提供了许多环境、生态、社会和经济效益。加拿大东部和美国的大部分森林是不同年龄的人工林或人工林，它们吸收大气中的二氧化碳（CO2）来抵消一些化石燃料的排放。在过去的几十年里，由于从过去的采伐、农业废弃和造林中恢复过来，这些森林一直是一个巨大的碳汇。然而，最近的研究表明，它们正在受到区域气候变化和极端天气事件（如干旱、洪水和热浪）的影响。气候变暖加速了水文循环。森林水循环的变化改变了其生长和土壤和植物养分循环，并对碳循环和水循环以及区域气候产生反馈。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，特别是对不同年龄的人工林和管理林分的影响，以充分了解其功能和对未来气候变化和极端天气事件的响应。我们建立了四个通量塔站点，包括三个针叶树年龄序列（75、40、12岁）的造林林和一个管理的落叶林（80岁）。这四个林分都位于长点地区自然保护局的流域内。***本研究将研究森林水文和养分循环变化对3个不同年龄针叶林和1个落叶林固碳潜力的影响，以及这些森林对未来气候变化和极端天气事件的响应。进一步发展陆地生态系统和水文模型(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方案-加拿大陆地生态系统模型（CLASS-CTEM+N）和区域水文模型（MIKE-SHE），探索森林生态系统的生物物理、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动相关通量和区域水文数据来探索气候变化和极端天气的影响。本提案还将根据政府间气候变化专门委员会（IPCC, AR5）的各种气候变化情景，利用ctem +N类生成的森林生长估计值，调查加拿大各地针叶树造林的经济吸引力和碳封存相关效益。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型中实施CLASS-CTEM+N模型将为联邦政府和IPCC制定政策提供一个评估工具，以生成未来气候情景，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.**