| Summary: | Ecosystems affect the thermal dynamics of permafrost soils via impacts on the surface energy balance. Changes in vegetation structure and function therefore have the potential to modify the thermal characteristics of permafrost soils, with knock-on effects for soil carbon cycling. In Siberian boreal forests, stem density and canopy cover are influenced by wildfire severity. In this study we examine differences in understory air and soil micrometeorology at six stands, two high-density (> 75% canopy cover), two medium-density (25-50% canopy cover), and two low-density ( < 25% canopy cover), all within a single fire perimeter that burned ca. 1940 near Cherskiy in northeastern Siberia. At each stand we measured photosynthetically active radiation (PAR), air temperature, and relative humidity at 1m above the ground, and measured soil moisture and temperature at the interface between the organic and mineral soil horizons (~10cm depth), and also within the mineral soil 10cm below the organic-mineral interface. Data collection began in July of 2014 and is ongoing, though there are gaps due to power outages. Canopy shading reduces PAR at higher density sites, and leads to lower soil temperatures during the growing season. Soil temperatures are also lower in higher density stands during winter, while soil moisture patterns are less clearly related to forest density.
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