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

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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.