An automated soil CO2 flux chamber system to study forest soil carbon budget

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The 68th UN General Assembly declared year 2015 the International Year of Soils (IYS2015; FAO, 2015). One of the main objectives of IYS2015 is advocating for rapid capacity enhancement for soil information collection and monitoring at all levels (global, regional and national). Soils are one of the most important factors for food security and essential ecosystem functions. Soils store the largest amount of organic carbon on Earth, with the largest stocks found in northern temperate and boreal regions. The dynamics of soil organic carbon are still poorly understood and are a major point of uncertainty in predicting future climate change scenarios due to anthropogenic actions. Forests play an integral role in the global carbon cycle by absorbing atmospheric carbon dioxide (CO2) through photosynthesis and eventually depositing it into the soil organic carbon pools through litterfall and root exudates. Forests can also loose carbon, through respiration by trees, mainly roots, and by soil microorganisms that decompose the deposited litter. Root respiration and respiration due to decomposition of organic matter by soil fauna is often referred to as total soil respiration. If a forest is in a state of equilibrium, the uptake due to photosynthesis and release due to respiration are balanced. However, this balance can be disturbed by land-use, such as harvesting and climate change. Many past studies on the impacts of tree harvesting on forest carbon dynamics have focused on above-ground carbon processes and stocks. A recent review has clearly identified an urgent need for studies that analyze the long-term impacts of harvesting methods on forest soil carbon dynamics, especially in boreal and northern temperate forests, which have the highest soil organic carbon stocks (Clarke et al 2015). The uncertainty resulting from the lack of knowledge on soil organic carbon dynamics under harvesting and climate change is limiting our ability to develop robust future climate forecasts and also forest management policies and guidelines that account for full carbon dynamics. In this proposal, we are requesting a state-of-the-art AUTOMATED SOIL CO2 FLUX CHAMBER SYSTEM, which will enable us to make long-term measurements of soil carbon dioxide (CO2) emissions in a recently harvested pine plantation forest located in southern Ontario. We will use these data to quantify and assess the harvest impact on the stand's carbon dynamics. These data will also be used to validate the land surface model, the carbon-nitrogen Canadian Land Surface Scheme (CN-CLASS), used in Canadian Earth System Model. Data collected in this project will add to our understanding of soil carbon dynamics, help improve climate predictions, and inform local forest managers on the impacts of harvests on forest soil carbon dynamics.