Forest Development on Rakata, Panjang and Sertung: Contemporary Dynamics (1979-1989)

Ten years of quantitative studies of forests on Krakatau demonstrate the vegetational difference resulting from multiple successional pathways. Multivariate analysis of the forest data indicates strong statistical separation of forest types within and between the islands. Current rates of forest growth and change within the Krakatau islands are found to vary considerably. The canopy architecture of Panjang and Sertung is observed to have changed dramatically over the past six years while the pace of change on Rakata appears relatively slow, particularly in the uplands. In an area studied in near-coastal, lowland Rakata, seedling recruitment of Neonauclea calycina is poor and its continued status as an overwhelmingly dominant species must be in question. A slightly more diverse forest appears to be developing below about 120 m elevation, in which Dysoxylum gaudichaudianum is an increasingly important component. Disturbance phenomena, ranging from continuing volcanism to individual tree falls, are found to be critical to an understanding of forest development on the islands. Despite the increasing role of Dysoxylum on Rakata our data indicate a continuing divergence of compositional types within the lowland forest.