Soil Gas Exchange in the Clearcut Site at Harvard Forest since 2011

Soil CO2 efflux was measured at the clear cut site beginning in 2011. That year a nearby spruce site was also measured for comparison. Soil respiration was measured in 2011 and 2012 with the LI-COR 6200 instrument and soil efflux was calculated later in the lab. In 2013 soil respiration was measured with the LI-COR 6400 instrument, which computed the fluxes internally. In 2012 three trenched plots were established at the clear cut site. Those were established by trenching a 2 x 2 meter perimeter to a depth of about 50 cm, severing any roots. The trenches were lined with heavy duty landscaping cloth and backfilled. Soil collars were installed in the middle of the trenched plots and measured in 2012 (1 large one used with the LI-6200 machine) and in 2013 (two smaller ones used with the LI-6400 machine). Sampling points were scattered around the site, along vegetation transects (near the EC tower, across the fire access road).

自2011年起，研究人员在皆伐迹地开展土壤CO₂排放通量（soil CO₂ efflux）观测；同年，还对邻近的云杉林样地进行同步观测以作对照。2011年与2012年，研究人员采用LI-COR 6200型仪器测定土壤呼吸（soil respiration），并于后续在实验室完成土壤排放通量的计算；2013年则改用LI-COR 6400型仪器开展土壤呼吸测定，该仪器可内置完成气体通量的计算。2012年，研究人员在皆伐迹地设置3个切根样地：开挖2 m×2 m的环形沟，深度约50 cm以切断所有根系，随后在沟内铺设高强度景观布并进行回填。研究人员在各切根样地的中央安装土壤环（soil collar），并分别于2012年与2013年开展观测：2012年使用1个大号土壤环配合LI-COR 6200仪器，2013年则使用2个小号土壤环配合LI-COR 6400仪器。采样点沿植被样带布设，分布于涡度协方差塔（EC tower）附近及防火通行道路沿线。