The Growth Studies In Hill Dipterocarp Logged-Over-Forest Reserves In Selangor, Malaysia

A growth study is important in the management of hill dipterocarp forest in Malaysia. The future of role in management of hill dipterocarp forest was depending on how well the remaining available resource is managed today. In order to achieve sustainability of forest management and to better understanding of forest stand and behavior, accurate growth data were important to outline the management strategies. Specific information on the behavior of particular forest stands pertaining to growth performance, mortality, density, structure and species composition is urgently required to evaluate the management system. This study addressed two main objectives;1) to determine the growth performance in hill dipterocarp forest after harvesting in term of number of tree, diameter, basal area and volume, and2) to determine the group species composition in hill dipterocarp forest. The study was conducted in a logged-over hill dipterocarp forest at Sungai Lalang Forest Reserve, Selangor. An area of about420ha of hill dipterocarp forest was selected for the study and felled at seven (7) different minimum cutting limits. The data consisted of year1992,1996,2000,2006and2011. Results show, the overall Diameter Mean Annual Increment of0.4518cm yr-1for all trees10cm to30cm DBH and Diameter Mean Annual Increment of0.5638cm yr-1for all trees30cm DBH is considerably lower than the rate of0.8to1.0cm yr-1assumed under Selective Management Systems. Although Diameter Mean Annual Increment of dipterocarp (Dipterocarp Meranti=0.6248cm yr-1, Dipterocarp Non Meranti=0.3314cm yr-1) were higher than that of non dipterocarp, their overall contribution to forest growth was small due to their lower stocking in the residual stand. Among the findings of the study on treatments, the study showed that growth of trees and stands were variable according to the treatments (cutting limits) applied with the growth trends felling rapidly after logging. Lower cutting limits resulted in higher growth increments compared with higher cutting limits. As for trees classes diameter30cm DBH and above, Treatment A (cutting limit:cut all trees≥30cm DBH) grew faster than Treatment H (No Cutting) with Diameter Mean Annual Increment=0.6725cm yr-1compared0.4532cm yr-1. Basal Area Mean Annual Increment showed0.0041m2ha-1yr-1for Treatment A and0.0032m2ha-1yr-1for Treatment H. While Volume Mean Annual Increment for Treatment A was0.0530m3ha-1yr-1and0.0470m3ha-1yr-1for Treatment H. Based on these growth rates increment, it was firmly believed that longer time is needed for the next cut for this study area. The results from this study have provided some understanding of growth in hill dipterocarp forest after harvesting. This should be useful for planning future research on growth and for guidelines for current management system of tropical forests, particularly in Peninsular Malaysia.