EFFECTS OF LAND MANAGEMENT AND A RECENT HURRICANE ON FOREST STRUCTURE AND COMPOSITION IN THE LUQUILLO-EXPERIMENTAL-FOREST, PUERTO-RICO

We compared the long-term effects (60 years) of land use practices and short-term effects (5 years) of a hurricane on forests in abandoned pastures, abandoned coffee plantations, and forested stands in the Luquillo Mountains of eastern Puerto Rico. There was no effect of management practices on species richness of trees and shrubs, nor on species diversity, species evenness, stem density, or basal area. However, there was a strong effect of management on tree species composition. Myrcia deflexa and Palicourea riparia dominated the former pastures, as well as Tabebuia heterophylla, a species which naturally invades pastures and which was subsequently established in many of the pasture areas by the USDA Forest Service. Abandoned coffee plantations were dominated by Guarea guidonia. Cecropia schreberiana, a pioneer species in the forest, was almost completely lacking in the old pastures indicating that this species is not an important component of forest recovery in abandoned pastures in the Luquillo Mountains. The abundance of Cecropia schreberiana in coffee and forest sites was inversely related to distance from the path of Hurricane Hugo (September 1989). Although the recent hurricane strongly affected the forest, it was unable to erase the signature of land use history on the species composition of these sites.