Tree composition

Initial composition (% of tree species volume) of each HDR zone forest, % of species volume at risk relatively to the total volume at risk (i.e., composition of volume at risk) and % of species volume at risk relatively to the total volume in each HDR zone for each projected period.各预测时段内，每个HDR区域森林的初始组成（以树种蓄积量百分比计）、受威胁树种蓄积量占受威胁总蓄积量的比例（即受威胁蓄积量的组成结构），以及受威胁树种蓄积量占该区域总蓄积量的比例。