CANOPY GAP DYNAMICS AND EFFECTS OF SELECTIVE LOGGING: A STUDY IN A PRIMARY HILL DIPTEROCARP FOREST IN MALAYSIA

Abstract

A systematic sampling was conducted in a primary hill dipterocarp forest of Peninsular Malaysia to evaluate the structure of the forest canopy before and after selective logging. The frequency distribution of gap area was strongly skewed. Before logging, the ridge had significantly higher gap area than hillside and ridgetop.However, after logging the canopy opening was much higher on the ridgetops due to high extraction ofcommercial trees. Unlike Brokaw’s method of gap measurement, the photographic measurements of gap area showed reasonably stronger correlation. The results of selective logging showed reduction of overall canopy cover by an average of 21%. Significant linear relationship was observed between loss of canopy trees and canopy opening. Due to variations in logging layout, the canopy openness varied significantly in the two study compartments. The opening of canopy was responsible for increased habitat heterogeneity followed by invasion of pioneer species. The effect of logging on percentage canopy loss was compared with a range of other studies. To maintain the canopy structure from destructive logging, this study strongly suggests site-specific cutting limit and adoption of appropriate harvesting plan, as well as skill development of forest workers and logging operators.