Treesearch

The landscape units map of Puerto Rico represents climatic, substrate, and topographic variation by integrating six climatic zones (Ewel and Whitmore 1973), six distinct substrates (Bawiec 2001, USGS 2005), five topographic positions or landforms (Martinuzzi et al. 2007), and prominent lakes and rivers (USGS 2005). Substrates were a simplified set of Bawiec’s (2001) twelve geologic terrane units and include cretaceous and tertiary limestone deposits, alluvium and other unconsolidated quaternary deposits, intrusive and extrusive volcanic formations and volcaniclastic sedimentary deposits...

This map shows the distribution of developed land cover in Puerto Rico (Martinuzzi et al. 2007). Developed land cover refers to urban, built-up and non-vegetated areas that result from human activity. These typically include built structures, concrete, asphalt, and other infrastructure. The developed land cover was estimated using Landsat 7 ETM+ satellite images pan sharpened to a spatial resolution of 15 meter. Multiple Landsat ETM+ images, ranging from the years 2000 to 2003, were used to create a mosaic of the island. The Iterative Self-Organizing Data Analysis Technique (ISODATA)...

This map shows the distribution of high and low density developed lands in Puerto Rico (Martinuzzi et al. 2007). The map was created using a mosaic of Landsat ETM+ images that range from the years 2000 to 2003. The developed land cover was classified using the Iterative Self-Organizing Data Analysis Technique (ISODATA) unsupervised classification (ERDAS 2003). Developed land cover refers to urban, built-up and non-vegetated areas that result from human activity. These typically include built structures, concrete, asphalt, and other infrastructure. The developed cover was divided into high...

requires producer nations to certify that exported supplies were obtained in a manner non-detrimental to the species’ survival in its role in the ecosystem. Non-detriment findings based on annual export quotas should verify that current harvest rates are sustainable with respect to total commercial stocks. In order to assess this impact, a method for converting export quality sawnwood volumes to numbers of standing trees is used to estimate the number of mahogany trees and forest area required to produce the original and revised 2007 export quotas set by Peru, correcting for systematic...

Quantification of the downed woody materials that comprise forest fuels has gained importance in Caribbean forest ecosystems due to the increasing incidence and severity of wildfires on island ecosystems. Because large-scale assessments of forest fuels have rarely been conducted for these ecosystems, forest fuels were assessed at 121 US Department of Agriculture forest service inventory plots on Puerto Rico, Vieques, and the US Virgin Islands. Results indicated that fuel loadings averaged 24.05 Mg ha1 in 2004–2006. Forest litter decreased from wetter to drier forest life zones. These...

This article is in Spanish. During an inventory to assess avian biodiversity among the critical watersheds that flow into the Pacific from Nicaragua, we captured a hybrid Vermivora chrysoptera (“Golden-winged Warbler”) with V. pinus (“Blue-winged Warbler”) known as Brewster’s Warbler (V. leucobronchialis). The capture ocurred on November 30, 2007 in dry forest (elevation c. 500m above see level) approximately 25 km from Managua. To the best of our knowledge this is the first recorded sighting documented with photos and morphometric data.

Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve our ability to manage forest fuels and predict fire behavior. In this study we assessed forest fuel characteristics in stands of differing moisture, i.e., dry and moist forests, structure, i.e., open canopy (typically...

In this study, we set up a wood decomposition experiment to i) quantify the percent of mass remaining, decay constant and performance strength of aspen stakes (Populus tremuloides) in dry and moist boreal (Alaska and Minnesota, USA), temperate (Washington and Idaho, USA), and tropical (Puerto Rico) forest types, and ii) determine the effects of fragmentation on wood decomposition rates as related to fragment size, forest age (and/ or structure) and climate at the macro- and meso-scales. Fragment sizes represented the landscape variability within a climatic region. Overall, the mean small...

Necromass stocks account for up to 20% of carbon stored in tropical forests and have been estimated to be 14–19% of the annual aboveground carbon flux. Both stocks and fluxes of necromass are infrequently measured. In this study, we directly measured the production of fallen coarse necromass (>2 cm diameter) during 4.5 years using repeated surveys in undisturbed forest areas and in forests subjected to reduced-impact logging at the Tapajos National Forest, Belterra, Brazil(3.088 S, 54.948 W). We also measured fallen coarse necromass and standing dead stocks at two times during our study.The...

The 250 landslides that simultaneously occurred in the Río Tarazá basin, Antioquia Department, in Colombia after the torrential rains of 19 and 20 May 2007 (Fig. 1) rank among the major rainfalltriggered disasters in this country (1). According to an official report, about 3000 ha, mostly covered by illegal cash crops, were wasted, thus reviving the discussion on the ecological impacts of illicit crops in Tropical America. These landslides and debris flow killed 13 peasants associated with coca bush (Erythroxylum coca) crops, forced evacuation of 67 people from indigenous reservations, and...