Comparing N-Tree Distance Sampling with Point and Plot Sampling in Northern Michigan Forest Types

Abstract

Abstract This study demonstrates the utility of n-tree distance sampling as an alternative to the more common point and plot sampling. This practical demonstration was conducted in Michigan's Upper Peninsula in three forest types: northern hardwood stands, plantation red pine stands, and clumped, mixed hardwood stands. Seven types of field sampling techniques were used: 1/5 ac and 1/10 ac fixed radius plot sampling, BAF 10 and BAF 20 variable radius point sampling, and n-tree distance sampling of 3, 5, and 7 trees. Estimates of mean board foot volume, cords, basal area, and number of trees per acre produced by n-tree distance sampling are biased, but when a bias correction factor is applied to the northern hardwood estimates, the results are equivalent to estimates from point and plot sampling. Investigation of bias in the plantation and clumped forests is ongoing. N-tree distance sampling is cost-competitive with the more traditional point and plot northern hardwoods. North. J. Appl. For. 11(1):12-16.