VARIABLE STOCKING VERSION OF PLONSKIS YIELD TABLES FORMULATED

Plonski's yield tables have been used extensively in forest management , economic evaluation, and as a basis for management planning in Ontar io. However, because these tables are based on site classes, they are not directly applicable to uneven-aged mixedwood cover types. A four-p arameter nonlinear model was employed to express various stand attribu tes as a function of stand age and recently developed basal area indic es for the major species in Ontario. The resulting variable stocking y ield functions will be applicable to even-aged stands as well as the b oreal mixedwood. Basal area index proved superior to site index for es timating both merchantable basal area and volume for the James River/M arathon data set representing boreal mixed from Northcentral Ontario. In addition, stand basal area index may be determined easily and inexp ensively via horizontal point sampling or prism cruising.