Predicting growth and yield models for Eucalyptus species in Aek Nauli, North Sumatera, Indonesia

摘要

This study was conducted primarily to develop a yield prediction model for Eucalyptus spp plantations in Aek Nauli, North Sumatera, Indonesia as a contribution to sustain development and management of forest plantations. Data for growth and yield model were collected from the inventory and permanent sample plots (PSPs). The data in this study used 650 rhombic plots consisting of 106 PSPs and 544 inventory plots with several variations of plot size. Stands' features referred to diameter, height, merchantable volume, age, species, spacing, site index, basal area, and density of Eucalyptus species. Models using initial age, specifically, model 2 was found consistently to be the best model in most Eucalyptus plantations. Among the models using initial and projection age, model 4 was the better one. Model 2 using original ages looks better than model 4 because of it is being more reliable and its sigmoid growth curve. Nonetheless, significant differences were noticed between different models for predicting the merchantable volume of Eucalyptus spp. Plantations. Growth and yield models can be used to identify the best growing species of Eucalyptus spp. E. hybrid is recommended for plantation in this study area because it had the highest of merchantable volume.