Treesearch

This book contains illustrations and descriptions, in English and Portuguese, of 172 tree species com­monly found in primary and secondary forests of the centrai Brazilian Amazon region, focussing on the Tapajos National Forest in western Para State. Photographic illustrations for each species include foliage (plus flowers and/or fruits for some species), seedling, bark, and trunk features that are intended to facilitate field identification. Written descriptions of each species include identification characteristics not apparent from illustrations, as well as information on wood and...

Relationships between landforms, soil nutrients, forest structure, and the relative importance of different disturbances were quantified in two subtropical wet steepland watersheds in Puerto Rico. Ridges had fewer landslides and treefall gaps, more above-ground biomass, older aged stands, and greater species richness than other landscape positions. Ridge soils had relatively low quantities of exchangeable bases but high soil organic matter, acidity and exchangeable iron. Valley sites had higher frequencies of disturbance, less biomass, younger aged stands, lower species richness and soils...

The tabonuco forest of Puerto Rico support a diverse population of tree species valued for timber, fuel, food, wildlife food and cover, and erosion control among other use. tree basal area growth data spanning 39 years are avaible on 15 species from eigth permanent plots in Luquillo Experimental Forest. The complexity of the rain forest challeges current forest standsmodeling techniques.

The development of the Hawaiian montane rainforest was investigated along a 4.1-million-year soil age gradient at 1200 m elevation under two levels of precipitation, the mesic (c. 2500 mm annual rainfall) vs. wet (> 4000 mm)age gradient. Earlier analyses suggested that soil fertility and foliar nutrient concentrations of common canopy species changed unimodally on the same gradients, with peak values at the 20,000-150,000 yr old sites, and that foliar concentrations were consistently lower under the wet than under the mesic conditions. Our objectives were to assay the influences of soil...

Population viability analyses for a number of endangered species have incorporated a metapopulation approach. The risk assessments of these viability analyses have indicated that some extant populations should be subdivided into numerous subgroups with exchange of individuals among them in order to reduce the chance of catastrophic loss of the species. However, routine application of a policy of extensive subdivision may have detrimental consequences for certain endangered species. We examine the Puerto Rican Parrot as a case history in which this policy is ill-advised. In 1989, a populatio...

Pueden utilizarse diferentes métodos para estudiar la distribución de una especie de ave terrestre o para llevar cuenta de los cambios en sus poblaciones. El método apropiado dependerá de si el objetivo es sencillamente documentar la presencia de una especie, o cuantificar su abundancia relativa, densidad poblacional, tendencias poblacionales a largo plazo, uso de hábitat, presunción de supervivencia, o las condiciones físicas de individuos de la especie. Una vez definido el objetivo es necesario considerar la selección del lugar de estudio, el total de unidades muestras, la hora del día,...