Construction of local volume table for natural mangroves in Peninsular Malaysia: case study of Sungai Merbok Forest Reserve, Kedah

Abstract

Tree volume tables have been recognized as one of the fundamental requirements in forest mensuration and management for providing estimates of timber volume to determine sustained yield and periodic increment. Mangroves one on important forests available in this country which also produced timber particularly for charcoal production. Thus, this study aimed at developing local volume tables for natural mangroves of Sungai Merbok Forest Reserve in Kedah. Two volume tables were developed for Bakau species (Rhizophora apiculata & R. mucronata) and Non-Bakau species (other species) based on relation between diameter at breast height (dbh) and gross stem volume (under bark and over bark). Test of accuracy by means of standard statistical measures and relative measures, were made on all equations, where the smallest value of mean square error (MSE) and mean absolute percentage error (MAPE) as the criteria for the best fitted equation to develop the local volume table. The local volume tables for Sungai Merbok Forest Reserve were constructed based on allometric model which were solved by mean of weighted least square (WLS). Practically, these volume table can be applied within the area, and not applicable to estimate timber volume in other mangroves areas. Nonetheless, other mangroves areas that having similar condition with Sungai Merbok Forest Reserve as natural mangroves may use the volume table until they construct for their own. Based on this study, the best fitted equations to construct local volume table for Sungai Merbok Forest Reserve are as follows: Bakau species: Vob = 0.00045 D2.02248 Vub = 0.00040 D2.04390 Non-Bakau species: Vob = 0.00088 D1.69929 Vub = 0.00084 D1.70310 Note: Vob = Over bark, Vub = Under bark and D = dbh in cm