VARIABLE STOCKING YIELD FUNCTIONS FOR THE BOREAL MIXEDWOOD IN ONTARIO

A measure of utilized site productivity, ''basal area index'' was rece ntly developed and used to construct variable stocking yield functions and tables for the boreal mixedwood of northcentral Ontario. Data fro m 197 permanent sample plots supplied by the James River/Marathon Pape r Company Ltd. were used. The resulting yield equations compare favour ably with previous ones and are more appropriate for the boreal mixedw ood. In addition, the basal area index employed has several advantages : 1) it serves as a valid measure of utilized site productivity which is better correlated with the main stand attributes than site index; 2 ) it produces variable stocking yield tables suitable for uneven-aged mixed species cover types; 3) unlike the site index, the basal area in dex may be estimated quickly, easily and inexpensively. The basic impr ovement in mixedwood yield estimation via basal are index should have broad applications for other stand types particularly for the disturbe d hardwoods of southern Ontario and those in eastern United States.