PATTERNS OF TREE MORTALITY IN AN ISLAND TROPICAL RAIN-FOREST SUBJECTED TO RECURRENT WINDSTORMS

In this paper we characterize the nature and extent of tree death of i ndigenous species in a natural rainforest community on La reunion isla nd (Indian Ocean). We predicted that tropical storms, frequent in the Mascarene Islands, may have an important effect on forest dynamics wit h most dead or dying trees being snapped or uprooted as a consequence of the strong winds. To do so, all dead trees were surveyed in a one-h ectare permanent plot at the Marelongue Natural Reserve, from June to July 1991. Diversity and size composition of live trees were known fro m a previous survey in the same plot. We observed two major patterns: First, a large number of dead trees (236, 16% of individuals greater t han or equal to 25 cm gbh) belonging to a large number of species (17) was found in the permanent plot. Second, for most species, a high pro portion of standing dead trees and a low proportion of snapped or upro oted were observed. Patterns of tree mortality and their consequences for gap characteristics appeared to be strongly related to the growth form and population dynamics of particular species.