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Prospect Hill的EMS塔范围内设置了40个半径为10米的圆形生物测量样地（biometric plots）。这些样地沿10条500米长的样线（transects）随机分布，样线以100米间隔从塔向西北和西南方向延伸。2001年，由于三个样地（G3、H3、H4）被海狸池塘淹没，我们将其从数据集中移除并停止了相关测量。1999年，为研究2000-01年冬季选择性采伐的影响，我们在Prospect Hill相邻的Simes Lot新增了6个半径为10米的圆形生物测量样地。2001年夏季，我们将采伐区域内的样地半径扩大至15米，并停止了其中一个未受采伐影响的样地（X4）的测量。此外，采伐还影响了原塔区的三个样地（A4、A5、B5），这些样地被纳入采伐样地组并扩大了规模。最终，数据集包含34个塔区样地和8个采伐样地。我们在每个样地采集了以下生态指标：树木生长、木质残体、凋落物、叶面积增量（LAI）、叶片化学性质以及土壤呼吸与湿度。