The evaluation of site factor studies.

SYNOPSIS The use of mathematical techniques distinguishes site factor studies from the closely related topics of site classification, survey and mapping. Selection of a homogeneous study area and the necessity of locating truly representative measurement plots that adequately sample the complete range of sites are important considerations influencing the accuracy and precision of these studies. Guidelines are given on the aims of the studies, sampling techniques, model building and testing and the reporting of results. Ridge regression and stepwise multiple discriminant analysis are two promising statistical methods that may be used in the future. Site factor studies will become more compatible with the objectives of multiple use policies.