Spatial structure of light and dipterocarp seedling growth in a tropical secondary forest

Variation in forest canopy openness influences the growth and survival of seedlings below, and is therefore of practical importance when wishing to restock a forest with valuable timber species after logging. In this study, growth and light environment of dipterocarp seedlings in an enrichment planting project in secondary lowland forest in Borneo were analysed using geostatistics, in order to determine the spatial relationships between canopy openness and seedling performance. Seedling growth was correlated with canopy openness measures up to 50 m away along planting lines but was uncorrelated across planting lines, because the dense understorey between planting lines blocked lateral light. It is recommended that planting be conducted in patches rather than along lines, so that understorey clearance can allow light from canopy gaps in all directions to reach seedlings.