SELECTION OF SITE TREES - THE COMBINED METHOD AND ITS APPLICATION

A new method is proposed for the selection of site trees. It is a combination of the two oldest and best-known methods: the fixed number and the fixed proportion methods. The fact that both methods have survived the trial of time suggests that neither is superior. The presented analysis shows that both methods are biased and that the biases are of opposite sign. Therefore, their estimates, when taken together, could produce an accurate site index. Weights needed to generate an unbiased estimate were calculated using permanent plots established in jack pine (Pinus banksiana Lamb.) stands in Ontario. For this species, weights were found to be constant and almost equal. In general, it is likely that weights vary with species tolerance. A practical guide to applications of the combined method for the construction of site index curves, estimation of site index, and preparation of yield tables is provided.