Faculty Research and Creative Activity

Document Type

Article

Publication Date

January 2009

Abstract

Estimation of tree density from point-tree distances is an attractive option for quick inventory of new sites, but estimators that are unbiased in clustered and dispersed situations have not been found. Noting that bias of an estimator derived from distances to the kth nearest neighbor from a random point tends to decrease with increasing k, a method is proposed for estimating the limit of an asymptotic function through a set of ordered distance estimators. A standard asymptotic model is derived from the limiting case of a clustered distribution. The proposed estimator is evaluated against 13 types of simulated generating processes, including random, clustered, dispersed and mixed. Performance is compared with ordered distance estimation of the same rank, and with fixed-area sampling with the same number of trees tallied. The proposed estimator consistently performs better than ordered distance estimation, and nearly as well as fixed area sampling in all but the most clustered situations. The estimator also provides information regarding the degree of clustering or dispersion.

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