Techniques and computations for mapping plot clusters that straddle stand boundaries

Abstract

Many regional (extensive) forest surveys use clusters of subplots or prism points to reduce survey costs. Two common methods of handling clusters that straddle stand boundaries entail: (1) moving all subplots into a single forest cover type, or (2)"averaging" data across multiple conditions without regard to the boundaries. these methods result in biased estimates of tree attributes (volume/acre, basal area/acre, etc.) and/or misclassification of discrete stand-area attributes (cover type, stand size, etc.). To circumvent the problems encountered with these approaches, a technique is described whereby subplots always are arranged in a fixed pattern, and trees are tallied by the cover type or "condition class" in which they occur. This involves mapping boundaries that bisect a subplot and proportioning subplot area by condition class. field and calculation procedures leading to unbiased estimates are given.

Citation

Scott, Charles T.; Bechtold, William A. 1995. Techniques and computations for mapping plot clusters that straddle stand boundaries. For. Sci. Monogr., Vol. 31: 46-61