Annual tree productivity in permanent plots within the H.J. Andrews Experimental Forest

Tree cores were taken from trees in permanent plots within the H.J. Andrews Experimental Forest to estimate annual bole biomass increment. The purpose of measuring this was to determine how many trees need to be sampled within a stand in order to determine NPP accurately. Increment cores were extracted from all trees greater than 5 cm diameter at breast height in each site and measured for annual growth increment (cm). This data was used to explore a method for using increment cores in combination with long-term permanent plots and remeasurement records to estimate annual bole biomass increment.

本数据集的树芯样本采自H.J.安德鲁斯实验林（H.J. Andrews Experimental Forest）内的永久样地，用于估算树干生物量的年增量。本次测量的核心目标为明确：在一处林分中需采样多少株林木，才能精准估算净初级生产力（Net Primary Productivity，NPP）。研究人员从每个样地内胸径大于5厘米的所有林木中提取增量树芯，并测定其年生长量（单位：厘米）。本数据集被用于探索一种结合长期永久样地与复测记录，利用增量树芯估算树干生物量年增量的研究方法。