DENSITY EFFECTS AND STAND DENSITY MANAGEMENT DIAGRAM FOR MERKUS PINE IN THE HUMID TROPICS OF JAVA, INDONESIA

The size and quality of produced timber are greatly affected by the suitability of planting density and the practice of thinning. Density effects on stand growth and development were evaluated in a spacing trial of merkus pine(Pinus merkusii Jungh. et de Vriese ), and these data were used to establish a stand density management diagram(SDMD). Growth performance in terms of diameter at breast height (D), total height(Ht) and mortality rate were monitored for 32 years when trees were 5-36 years old. Mortality and D growth were positively density related, but H growth was not affected by density. During the measurement period, tree density decreased from 7779 to 679 trees/ha for the closest spacing and from 943 to 514 trees/ha for the widest spacing. Results suggested that optimal harvesting was at about 30 years of age if no thinning occurs. The SDMD was established to predict the course of stand development in merkus pine. The simulation of stand growth under 2m x 3m spacing and thinning options was demonstrated in a SDMD, and suggested reasonable flexibility for practical application. We recomemend using this SDMD as a tool to reexamine the thinning regime for enchancing forest productivity and wood utilization.