CROWN DIAMETER PREDICTION MODEL FOR PLANTATION-GROWN <em>NEOLAMARCKIA</em> <em>CADAMBA</em>

Abstract

AHMAD ZUHAIDI Y. 2013. Crown diameter prediction model for plantation-grown Neolamarckia cadamba. This paper reports on the development of a prediction model for plantation-grown Neolamarkcia cadamba using crown diameter as the main parameter. Data were collected from private plantations in Sandakan, Sabah; Sabah Softwood Limited in Tawau, Sabah; WTK Group of Plantations in Sibu, Sarawak and plantations in Setul Forest Reserve, Negeri Sembilan. The plantations were 4 and 10 years old. The ordinary least square method was used in analyses with six models using transformed, untransformed and weighted crown diameter as the response variables as well as diameter at breast height (dbh) and dbh² as the independent variables. With values of coefficient of determination (r²) and standard error of fitted regression (or root mean square error), the Furnival index (FI) obtained was used as the final selection criterion for the best fitted model. The results indicated that model 5, having weighted response variable, gave the lowest FI at 0.017 and was thus selected as the most appropriate crown diameter prediction model for N. cadamba.