Mass and energy exchange between land surfaces and the atmosphere in central Canadian ecosystems

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Potential responses to climate change include alteration of landscape management to either decrease emissions or increase sinks of greenhouse gases. This research aims to evaluate the effects of some of these management options through measurement of the net flux of greenhouse gases using micrometeorological techniques at the field scale. The program includes both forested and agricultural landscapes of central Canada (focusing on Manitoba and Saskatchewan), with special attention to vegetation changes and disturbances, such as fire. The activities include a rigorous evaluation of the statistical and spatial representativeness of using eddy covariance flux towers to measure net fluxes when comparing different management treatments. This is important to the global measurement community to justify lack of replication and to gain confidence in our ability to inform policy decisions on landscape management choices. Another activity is the measurement of carbon dynamics of boreal forests, especially related to fire. This work builds on data sets that have been collected from flux towers in northern Manitoba and central Saskatchewan to answer global hypotheses related to the role of mature forests in net carbon exchange, and the effects of fire on the carbon cycle. In particular, the data sets will provide the length of time required for forests to recover from combustion emissions but uncertainty must be evaluated if these data are to be used to validate mathematical models. A third activity is the measurement of the effect of agricultural land management practices on greenhouse gas exchange. This involves changes to cropping practices where land is converted from perennial to annual crops, or from annual to perennial crops. The exchange of carbon dioxide and nitrous oxide both need to be considered, and will be measured at several locations. The program focuses on high-quality training of students so that they learn measurement and analysis techniques related to practical global and local questions to improve our understanding of the role of the landscape on greenhouse gas and energy exchange.