Tropical rain forest recovery from cyclone damage and fire in Samoa

In 1990 and 1991, Samoa was struck by two cyclones, Ofa and Val. In the Taf ua Rain Forest Preserve on the island of Savai'i, one part of the forest al so burned after the first cyclone. Here we report on patterns of regenerati on and changes in tree species composition in the Tafua lowland rain forest after five years of recovery from cyclone and fire disturbance. In the unb urned area, tree canopy cover increased from 27 percent after the last cycl one to 58 percent, and in the burned area from below 12 to 49 percent. Nine of the ten most common tree species decreased in relative abundance in the entire forest after the last cyclone. One fast growing pioneer species, Ma caranga harveyana, now makes up 42 percent of the total number of trees (>5 cm DBH) in the unburned area and 86 percent in the burned area. Large inte rspecific differences occur in size distribution and there are at least fou r distinguishable regeneration patterns, which may be related to shade tole rance. Mean number of species per plot was generally higher in the unburned area than in the burned area, while the Shannon evenness index was higher in the unburned than in the burned area only for trees above 1 cm DBH. Spec ies with fruits known to be fed upon by birds and/or bats generally made up a larger proportion of all trees in the burned than in the unburned area. In contrast to other studies of post-cyclone regeneration, in which recover y is often rapid due to resprouting of trees, recovery in the Tafua forest was a slow process with regeneration more dependent on vertebrate seed disp ersal than on resprouting.