Peterson Shirttail random selection for mortality

This is an Excel spreadsheet, containing all trees in the Shirttail site. For each tree, a random number between zero and unity is assigned for each of 20 separate iterations; the random number for each iteration is a separate column with the headings "Rand1", "Rand2", "Rand3", etc. These numbers form the basis of selection of trees for the 20 iterations of random selection of trees to simulate mortality. For example, at Shirttail 257 trees were fallen out of the 319 predisturbance trees. In iteration 1, the random numbers and associate trees (with coordinates) are sorted from smallest to largest, and the 257 trees with the lowest random numbers in column "Rand1" are selected to randomly simulate mortality; these are then input to the NDF algorithm. The same process is repeated 20 times, but because the random numbers are different in each column, the 257 trees selected in each of 20 iterations is a different subset of the predisturbance trees.本数据集为一份Excel电子表格，收录了Shirttail样地内的全部林木。针对每一株林木，在20次独立迭代过程中，均会为其分配一个介于0至1之间的随机数；每次迭代对应的随机数单独作为一列，列标题依次为“Rand1”“Rand2”“Rand3”等。这些随机数即为20次林木随机选择模拟林木死亡过程的选树依据。例如，在Shirttail样地中，扰动前共有319株林木，其中257株发生倒伏。在第1次迭代中，将随机数与对应林木（含坐标信息）按随机数值从小到大排序，选取“Rand1”列中随机数最小的257株林木以随机模拟林木死亡过程；随后将该选树结果输入NDF算法。上述流程共重复20次，由于每一列的随机数互不相同，因此20次迭代中每次选取的257株林木，均为扰动前林木种群的不同子集。