Effects of logging and line planting treatment on canopy openness in logged-over forests in Bornean lowland dipterocarp forest

In logged-over forests, altered light conditions with logging induce pioneer species invasion and reduce commercial value. In Indonesia, reduced impact logging (RIL) methods have been applied to mitigate the logging effects, and line planting of useful species has been conducted in some production forests. However, quantitative assessments of canopy openings during RIL and line planting treatment are insufficient. Line plating involves 3-m strip cutting lines. The effects of these methods on canopy openness are poorly understood. This study assessed the effects of different logging systems on light conditions using hemispherical photographs taken in plots set in primary forests, forest logged over using RIL, and forest treated with strip cutting after RIL. Photographs were also taken along strip cutting lines. The comparison of canopy openness among the three types of sites revealed that logging activities had significant effects on light condition. High levels of canopy openness were found along skid trails and logging gaps following the trails. Therefore reducing the impact on light conditions should be considered when planning skid trails. Between the logged-over forest plots with and without the strip cutting lines, there was no significant difference in the mean canopy openness. However, strip cutting treatment affected to sun fleck duration in the forest floor. It might influence to following dynamics. And there were large differences in canopy openness along each line which would cause variations in the growth of planted trees.