"Carbon and water balances of hybrid poplar plantations, and lodgepole pine and Douglas-fir stands"

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The goal of my research is to better understand the carbon (C), water and energy balances of hybrid poplar (HP) plantations, lodgepole pine stands recovering from mountain pine beetle (MPB) attack, and managed coastal Douglas-fir (DF) stands. A micrometeorological method, eddy covariance (EC), will be used to make year-round measurements of net ecosystem productivity (i.e., C sequestration or loss) and evapotranspiration (i.e., water use). One aim of my HP research is to determine the capacity of different-aged HP plantations in the Prairie region to sequester C as plant biomass (for fibre or bioenergy production) and soil organic matter. Because of the high water requirements of HP plantations, a key objective will be to determine the sustainability of extensive plantations by comparing water use and precipitation. Effects on the rate of water drainage to the water table will be determined and the implications for the regional water balance assessed. In my MPB research, an important objective is to measure the rate of recovery of the C balance in non-harvested stands when killed trees are starting to fall with the possibility of increasing decomposition rates. In addition, the feasibility of using partial salvage harvesting (removing only pine trees) rather than clearcut salvage harvesting (which results in large C losses) will be determined by assessing wind damage and C sequestration in the former. A process-based forest production model (3PG) will be used with several management scenarios to estimate likely near-future changes in the C balance in the vicinity of our MPB research sites. My DF research will focus on measuring the strong growth response of a 23-year-old stand fertilized in 2007 as it begins to crowd out competing understory vegetation. In addition, the losses of C from a clearcut resulting from the harvesting (in Jan 2011) of a recently-fertilized 61-year-old stand will be measured using EC until 2013. Controlling processes will be studied using measurements of respiration by soil and woody harvesting debris, soil-surface methane and nitrous oxide fluxes, rates of C transport in stream water, and post-harvesting changes in the soil water regime.