Sixty-two years of change in subtropical wet forest structure and composition at El Verde, Puerto Rico

a plot established in 1943 in a subtropical wet forest at the luquillo experimental forest of puerto rico has been assessed periodically for changes in species and size of all trees >4cm diameter. forest dynamics on a 0.72ha plot (ev-3) at 400masl at el verde show recovery principally from hurricanes of 1928 and 1932, timber stand improvement in 1958, and from hurricanes hugo and georges in 1989 and 1998. damage from hurricane hugo only temporarily slowed aboveground biomass accretion of the developing forest. stand increases in basal area and biomass continue to be due principally to growth of the dominant overstory species, dacryodes excelsa and manilkara bidentata, ingrowth of which was stimulated by hugo. the pioneer species cecropia schreberiana filled gaps abundantly following the hurricane and the understory tree psychotria berteriana proliferated. ingrowth of prestoea montana has been greater than for all other species since 1976 and was stimulated by hugo and georges as well as prior hurricanes, so that by 2005 it was the most abundant species. hurricane hugo caused low mortality among the largest trees on the plot. as a few species have become more dominant species evenness has declined. species richness is only slightly greater today than in 1943. results are discussed in terms of "building" and "thinning" phases associated with major hurricanes. hurricanes have stimulated the addition of species to the forest in "building years," but have maintained that richness in the intervening "thinning years", lending credence to the "intermediate disturbance hypothesis".