Biomass Inventories at Harvard Forest EMS Tower since 1993

In 1993, we installed 40 circular, 10 m radius biometric plots in the footprint of the EMS tower on Prospect Hill. We randomly placed the plots within 100 m increments along ten 500 m transects that extend from the tower in the northwest and southwest directions. In 2001, we removed three plots (G3, H3, H4) from the datasets and ceased measurements there due to their inundation by a beaver pond. In 1999, we installed 6 additional circular, 10 m radius biometric plots on the Simes Lot, adjacent to Prospect Hill to study the effects of a selective harvest that occurred there in the winter of 2000-01. In the summer of 2001, we expanded the harvested plots in size to 15 m radius and ceased measurements at one plot (X4) because it was unaffected by the harvest. The harvest also affected three of the original tower plots (A4, A5, B5), which were expanded in size as a part of the harvest plot group. Consequently, there are 34 tower plots and 8 harvest plots. We have taken the following ecological measurements at each site: tree growth, woody debris, litter, leaf area increment (LAI), leaf chemistry, and soil respiration and moisture.1993年，我们在展望山（Prospect Hill）的EMS塔楼占地范围内布设了40个半径为10米的圆形生物测量样地（biometric plots）。我们沿从塔楼向西北、西南方向延伸的10条500米样带，以100米为间隔随机布设了这些样地。2001年，由于3个样地（G3、H3、H4）被海狸池塘淹没，我们将其从数据集移除并停止了该处的测量工作。1999年，为研究2000-2001年冬季在此开展的选择性采伐的影响，我们在紧邻展望山的赛姆斯地块（Simes Lot）额外布设了6个半径10米的圆形生物测量样地。2001年夏季，我们将该采伐样地的半径扩大至15米；同时因样地X4未受采伐影响，我们停止了对其的测量。此次采伐还影响了原塔楼样地中的3个（A4、A5、B5），我们将其纳入采伐样地组并扩大了其样地规模。最终，当前共有塔楼样地34个、采伐样地8个。我们在每个样地开展了以下生态监测：树木生长、木质残体、枯落物、叶面积增量（LAI）、叶片化学特性以及土壤呼吸与土壤湿度。