Canopy height recovery after selective logging in a lowland tropical rain forest

Abstract

The effects of selective logging on canopy height were studied in a lowland tropical rain forest in Pasoh Forest Reserve, Peninsular Malaysia. Canopy height was measured in 2003 and 2011 by using an airborne light detection and ranging system and mapped on a 2.5-m grid over logged and primary forest plots. The logged forest plot was in an area where a selective logging operation had been conducted in 1958, whereas the primary forest plot has no trace of any major human-induced disturbances. The average canopy height in the logged forest plot increased from 23.6 m (2003) to 25.8 m (2011), but both of these heights were still significantly lower (P < 0.0001) than in those in the primary forest plot (28.7 m in 2003 and 30.4 m in 2011). The coefficient of variation and canopy height diversity (H′) were also lower in the logged forest plot, suggesting that the highly heterogeneous canopy height commonly seen in the primary forest in this region had not fully recovered even 53 years after the logging operation. Simulation analysis revealed that it will take at least another 16 years from the last canopy mapping (2011) for full recovery.