January 6, 2020
https://www.linkedin.com/posts/activity-6619975361671286784-Nhku
PTAEDA 4.1 and the FMRC forest sampling simulator can be used to evaluate statistical precision, accuracy, and cost of alternative forest inventory designs. The examples show in silico estimates of sampling error (precision) on the y-axis and bias (accuracy) on the x-axis for trees/acre obtained from 30 sampling units of varying size and shape at ages 11 and 24 years. The number of measured trees/sampling unit is included as an index of cost. In the 11-year-old-stand, point samples with BAF 15 or larger exhibited high sampling error, high bias, or both. Also, large numbers of trees/sampling unit must be measured to obtain less than 10% sampling error and less than 10% bias. In the 24-year old stand, the number of measured trees/sampling unit is related to both precision and accuracy. Point samples with BAF 10 or less and several fixed-area plots resulted in less than 10% sampling error and less than 10% bias but with a smaller number of measured trees/sampling unit than in the younger stand.