Carbon sequestration and greenhouse gas emissions in forests, wetlands and agricultural fields

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***The goal of my research is to better understand the processes and environmental controls that determine carbon (C) sequestration and greenhouse gas (GHG), namely CH4, CO2 and N2O, emissions in terrestrial ecosystems including forests, wetlands, and agricultural fields. This research aims to advance the development of technology and policy to better manage terrestrial ecosystems to increase C sequestration, minimize GHG emissions and the impacts of climate change, while maximizing productivity and water use efficiency. Net ecosystem production (NEP), evapotranspiration, and CH4 and N2O fluxes will be measured using the eddy-covariance (EC) technique. I will also use flux chamber measurements to quantify the temporal and spatial variability of, and effect of management on, soil GHG fluxes, and assess the reliability of scaling up chamber measurements to stand and field level. ***One of my aims will be to refine the partitioning of net ecosystem exchange of CO2 between ecosystem respiration (R) and gross ecosystem photosynthesis (GEP) by estimating light inhibition of leaf respiration during the daytime in a 29-yr-old West-Coast Douglas-fir stand. This will be accomplished by making EC measurements of 13CO2 and 12CO2, fluxes using a tunable diode laser - infrared gas analyzer system, with the isotopic flux ratios of NEE (δNEE) and R (δR) estimated from the ratios of the 13CO2 to 12CO2 fluxes during daytime and nighttime, respectively. In my research on mountain-pine-beetle impacted forest in the BC Interior, the focus will be to further improve the process-based forest growth model 3-PG that my PhD student Gesa Meyer has modified to include the effects of insect attack on a stand by treating understory and overstory growth separately, to include heterotrophic respiration (Rh) for determining NEP, and the extent of the increase in Rh due to increased coarse woody debris from dead trees. In an urban bog in the Lower Fraser Valley (LFV), the focus will be to understand the dynamics in the dominant processes controlling EC-measured CH4 and CO2 fluxes with the progression of restoration by rewetting, and to compare distinct sites characterized by peat-moss depth, soil wetness, and vegetation variations within the bog using mounted chambers to continue measurements during flooding events. The objective of my research on agricultural land is to improve our understanding of the processes controlling GHG emissions in major agricultural cropping systems in the LFV. This will involve studying the production, consumption, and transport of GHGs in the soil in situ using continuously sampled soil air at several depths in order to apply the gradient technique. ***These research projects will help understand and quantify the C balance of, and the GHG fluxes from, terrestrial ecosystems, and their potential in climate change mitigation, and also provide an excellent training environment for highly qualified personnel.**