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 the Simmes 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铁塔占地范围内布设了40个半径10米的圆形生物测量样地（biometric plots）。我们沿着从铁塔向西北、西南方向延伸的10条500米样带，以100米为间隔随机布设该批样地。2001年，因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监测工作。1999年，我们在毗邻展望山的西姆斯地块（Simmes Lot）增设了6个半径10米的圆形生物测量样地，用以研究2000-2001年冬季该地块开展的选择性采伐的影响。2001年夏季，我们将受采伐影响的样地半径扩大至15米；同时停用了样地X4，因其未受本次采伐波及。本次采伐还影响了原铁塔样地中的3个（A4、A5、B5），这些样地被纳入采伐样地组并同步扩大了监测面积。综上，当前共有铁塔样地34个、采伐样地8个。我们在每个样地开展了以下生态监测工作：树木生长、木质残体调查、枯落物监测、叶面积增量（Leaf Area Index, LAI）、叶片化学组成分析，以及土壤呼吸与土壤湿度测定。