Long-term changes in structure and composition following hurricanes in a primary lower montane rain forest in Puerto Rico

Abstract

Ridges within the lower montane rain forests (sensu Beard) of the Caribbean Basin are dominated by Dacryodes excelsa, a tree species known as tabonuco in Puerto Rico and gommier in the Lesser Antilles. Periodially, hurricanes traverse the islands causing changes in structure, species composition, and dynamics of forests. The chronology of post-hurricane vegetation change from 1946 to 2010 on a 0.4 ha ridge plot approximately 380 m in elevation in the Luquillo Experimental Forest of northeastern Puerto Rico showed: (1) defoliation, breakage, and uprooting by wind accompanied by immediate mortality resulting in a loss in forest structure, including stem numbers, tree height, and biomass; (2) delayed mortality of some impacted trees, along with prompt, abundant ingrowth of Cecropia schreberiana, and the other secodary species, increasing the number of stems within the forest; (3) a post-hurricane increase in diamater growth and biomass accumulation for approximately 20 years, followed by a decline in both rates; (4) a high post-hurricane survival and increase in dbh increment of Dacryodes excelsa; (5) a post-hurricane increase in species richness for 20 years when primary and secondary species grow together, followed by a decline due to competition; (6) asymptomatic conditions for stems, biomass, and number of species after more than 40 years. In addition, related studies in the same forest type showed that hurricanes and thinning evoke comparable growth responses. This study should be of regional interest because Puerto Rico's lower montane rain forest shares similar environmental conditions as well as tree species with the mountainous Antilles.

Citation

Weaver, P.L. 2013. Long-term changes in structure and composition following hurricanes in a primary lower montane rain forest in Puerto Rico. Bois et Forets des Tropiques. 317: 7-21.