Structure and floristic composition of a dipterocarp primary forest in East Kalimantan

Abstract

Forest inventories conducted in Indonesia (Berou District, East Kalimantan) highlighted the main features of the Dipterocarpaceae primary forest. Dipterocarpaceae species accounted for 25 % of the stand (diameter ≥ 10 cm), 50 % of the basal area and 60 % of the standing volume. In three primary forest control plots (total area 12 ha), 538 taxa were inventoried, with a mean of 182 different tree species per hectare.
The Berau forest, in terms of stand density, basal area and standing volume, resembled Borneo forests, and especially Sabah forest. However, it had a much higher proportion of Dipterocarpaceae species, which could be due to the absence of major climatic variations in this region. Although floristic variability within the stand has been explained by edaphic factors in previous studies, the present results indicated that forest dynamics are critical in determining the species composition of the forest.