The Dry Forests of Puerto Rico’s South Coast

Abstract

The subtropical dry forests of Puerto Rico are found mainly on the island’s southwest coast in the rain shadow of the central mountain system. Studies of the 4000-ha Guánica Forest have provided basic information on ecology and management potential. Even on the more favorable sites, the dry forests are smaller in stature and biomass, lower in biodiversity, lower in productivity, and more seasonally pulsed in tree growth, reproductive cycles, and organic matter turnover than forests in areas of higher and less seasonal rainfall. The limestone-based soils are primarily mollisols, characterized by high organic matter, low bulk density, and high pH. Soil nutrient contents are relatively high, but less than 2% of the P is in a readily available form. Nevertheless, because of the proportionately small nutrient inventory in biomass, it appears that the soil nutrient pool could sustain several rotations of aboveground biomass removal without depleting reserves to a level that would immediately jeopardize forest productivity. Relatively rapid recovery of a cut-over dry forest occurs if stump and root sprouts are allowed to survive. Because of sprouting, most plant species are reestablished within 3 years, and aboveground biomass accumulates to almost half of precut levels within 13 years. Chronically disturbed sites, however, are much slower to recover. On the basis of the available ecological data, we make recommendations concerning the conservation, utilization, and management of dry forests and offer suggestions concerning research needs.