Author : Janes Siahaya

Summary : This study sought to find an appropriate formulation and specification of a yield prediction model and to construct yield tables for Pinus merkusii plantations in Java, Indonesia. The study aimed to: (1) explore the use of the simultaneous equations model for yield prediction and to compare the results of the estimation procedures used, namely: ordinary least squares (OLS) and two-stage least squares (2 SLS); (2) compare the simultaneous equations model with single equations model; and (3) compare the results obtained from the model developed with the results obtained by Ferguson in 1954. The coefficient of the simultaneous equations model were estimated using the OLS and 2 SLS. For the single equations model, the coefficients were estimated through the OLS method. In this study, the model was developed for both main and whole stands. Data were obtained from a sample of 545 observations as an experimental series taken from 114 permanent rectangular plots established in West and East Java. With the genetic variation and management regime held constant, yield was found to be adequately affected by stand age, site index, original stand spacing, thinning intensity, and stand basal area.