A simple step-wise procedure for predicting stand development of Acacia mangium plantations based on the maximum size—density line in South Sumatra, Indonesia

Abstract

A simple step-wise procedure for predicting the course of stand development on log—log coordinates of stand density and quadratic mean diameter was presented based on a distance of measurement from the maximum size—density line of Acacia mangium. This procedure first predicts annual increment of diameter with a multiple linear regression having the distance, site index, and current diameter as independent variables, and then the associated mortality is calculated with the rate of reduction in stand density to the diameter growth derived from a fitted trend with the distance. The cumulative predictions, starting at 3 years after planting until 9 years of age, agreed well with the observations of group-age means of measurements calculated for the three levels of initial density. Contrasting trend of basal area growth between the three levels of initial density and those for their site index: the differences were decreasing in the former while they remained constant in the latter, was clearly illustrated with the procedure indicating a good potential for use in yield prediction. The simulations for stand growth under different spacing and thinning options were demonstrated in a stand density control diagram suggesting reasonable flexibility for practical application.

Key words:

• Acacia mangium
• Basal area
• Maximum size-density line
• Quadratic mean diameter
• Self-thinning