EARLY DIAMETER GROWTH OF TREES IN PLANTED FOREST STANDS

A model to describe early diameter growth of trees in planted forest s tands is presented. Relative diameter growth rate of free-grown trees is used to estimate potential diameter growth of competitively grown t rees of the same species and age. The effect of competition on the abi lity of competitively grown trees to attain their growth potential is assumed to be a function of site resource availability-growing space. Data from free-grown trees of the correlated curve trend projects in S outh Africa are used to estimate growth at several spacings at other S outh African sites and in Hawaii. The model produces typical current a nnual and mean annual growth curves as well as branched curves of diam eter growth over time at different spacings. It is consistent mathemat ically with relative density concepts. Because individual tree diamete r and stand volume are the most important factors in harvesting costs, the model can serve as a decision support tool to assist forest plant ation managers choose how many trees to plant per unit area for optimu m cost-efficiency in short-rotation intensive-culture operations.