Data logger systems for a field warming experiment

点击翻译按钮获取中文摘要

Climate change caused by increases in greenhouse gasses has been predicted to occur first and fastest at high latitudes. In the boreal forest, records of tree growth are already showing signs of recent climate warming. At the same time, there is an upward trend in the amount of boreal forest that burns each year, especially in western Canada, where there have been increases in the duration of dry summer weather. These burned forests will need to regenerate under climate conditions likely to be very different from what they experienced in previous cycles of forest regeneration. How will ongoing climate warming affect the ability of these forests to re-establish after fire, particularly in drier areas where mature trees are already showing signs of increased drought stress?     This research proposes to investigate how one aspect of a changing climate, increased soil temperature, may affect patterns of forest regeneration in an area of dry boreal forest in southern Yukon Territory. A soil warming experiment will be established that uses circulation of solar-heated water to warm surface soil during the summer by 2-4 °C. This experiment will be set up across a soil moisture gradient within a large area of white spruce forest that burned in 1998. Patterns of natural seedling establishment in the burn indicate that white spruce has regenerated very poorly at the driest sites in the burn, while seedlings are abundant in cooler and moister sites on north-facing slopes and valley bottoms. Planting trials of white spruce and other forest co-dominants will be applied to warmed and control plots to test whether soil warming and drying is likely to be a limiting step in forest regeneration after fire in this area. The experiment will be duplicated across dry, moist, and wet sites to determine if there differences in site moisture availability affect the response of forest regeneration to soil warming. Results of the experiment will indicate how increased warming in dry regions of boreal forest may alter patterns of forest renewal after fire.