Treesearch

Failures in reforestation are often attributed to nutrient limitation for tree growth. We compared tree performance and nitrogen and phosphorus relations in adjacent mixed-species plantings of contrasting composition, established for forest restoration on Ultisol soil, originally covered by tropical semi-deciduous Atlantic Forest in Southeast Brazil. Nutrient relations of four tree species occurring in both planting mixtures were compared between a legume-dominated, species poor direct seeding mixture of early-successional species (‘‘legume mixture’’), and a species-diverse, legume-poor...

During the month of June 2008 we collected arthropods active on the surface of the ground in a forest of Castilla elastica located in the northern karst’s Tallonal Reserve in Arecibo, Puerto Rico. In each of 4 plots of 10 m x 10 m we placed three randomly distributed pitfall traps. The traps, which allowed the passage of organisms smaller than 5 mm wide, remained on the field for seven days. The samples collected in the field were taken to the laboratory for subsequent identification and counting of organisms. We found 13 taxa belonging to three classes of arthropods, with an average...

In Puerto Rico, brackish water wetlands were dominated by Pterocarpus officinalis previous to extensive deforestation due to agriculture. Today remnant wetlands are limited to small areas that are threatened by rise in sea level. We examined the root nodules of P. officinalis in montane and coastal sites and at 0, 10, 20 cm from the surface to determine if site conditions relate to the formation and characteristics of nitrogen fixing nodules. We found no significant difference in nodule quantity between montane and coastal ecosystems. However, although all the montane sites experienced...

Millipedes, among other soil fauna, are important components of ecosystems because of their role in nutrient cycling. In this study, we quantified the density, biomass, and richness (in terms of order) of millipedes along a toposequence (ridges, slopes, and valleys) and different ground layers (litter, humus, 0-5 cm soil depth, and 5-10 cm soil depth) in a subtropical wet forest in Puerto Rico. Millipedes were surveyed from twelve 50 x 50 cm plots (3 topographic positions x 4 replicates) by hand sorting. Four orders of millipedes were found in El Verde tabonuco forest: Stemmiulida (the...

During June 17 and 18, 2008, a Castilla elastica forest located in El Tallonal, municipality of Arecibo, functioned as a carbon sink. The net photosynthetic rate ranged from 14.28 (native species) and 21.96 (C. elastica) g C m-1 day-1 and respiration of leaves, stems, and soil varied from 13.76 (native species) and 16.88 (C. elastica) g C m-1 day-1. The net accumulation of carbon in the forest ranged from 0.52 (native species) and 5.08 (C. elastica) g C m-1 day-1. These values may change significantly during days with low rates of photosynthesis and depending on how respiration rates in...

Puerto Rico faces a number of problems common to much of the world. Population is increasing while land area is not, and there are reassessments of land use policy and practice to accommodate growing populations, shifting economies, and changing public value systems. Puerto Rico shares similarities with the Eastern United States with its history of agricultural abandonment, relatively high population density, and abundance of “forested” suburban areas in the wildland-urban interface. Puerto Rico has affinities with other tropical regions with high biodiversity and an abundance of rare...