Treesearch

This paper was aimed at establishing the relations between some soil properties and the growth of P. taeda on its main area of commercial plantation in Argentine Mesopotamia. It was hypothesized that main cause of productivity reduction is soil depth and effective plant- available soil volume rather than nutrient content. The study area was located in Corrientes and Misiones provinces from 28º 30’ S to 25º 30’ S. Thirty-one sites were selected , in all of which : 1- soil samples were obtained for nutrients and bulk density determination, 2- dasometric variables were measured and Site Index...

The reality confronting ecosystem managers today is one of heterogeneous, rapidly transforming landscapes, particularly in the areas more affected by urban and agricultural development. A landscape management framework that incorporates all systems, across the spectrum of degrees of alteration, provides a fuller set of options for how and when to intervene, uses limited resources more effectively, and increases the chances of achieving management goals. That many ecosystems have departed so substantially from their historical trajectory that they defy conventional restoration is not in...

Hurricanes, cyclones, and typhoons are common disturbances in many island and coastal forests. There is a lack of understanding of the importance to forest biota of the two major physical aspects that occur simultaneously during a hurricane: canopy disturbance and detritus (debris) deposition onto the ground. Using a replicated factorial design, our study involved experimentally determining the independent and interactive effects of canopy opening and debris additions to the forest floor on densities of coqui frogs (Eleutherodactylus coqui). Coquies are the dominant amphibian, and second...

The mangrove environment is not globally homogeneous, but involves many environmental gradients to which mangrove species must adapt and overcome to maintain the familiar structure and physiognomy associated with the mangrove ecosystem. The stature of mangroves, measured by tree height, decreases along the following environmental gradients from low to high salinity, low to high wind speed, high to low air temperature, high to low nutrient availability, and high to low rainfall. Litterfall, an indirect measure of mangrove productivity, decreases along the same environmental gradients....

The seasonal dynamics of foliage arthropod populations are poorly studied in tropical dry forests despite the importance of these studies for understanding arthropod population responses to environmental change.We monitored the abundance, temporal distributions, and body size of arthropods in five naturalized alien and one native tree species to characterize arthropod seasonality in dry novel Prosopis–Leucaena woodlands in Puerto Rico. A branch clipping method was used monthly to sample foliage arthropod abundance over 39 mo. Seasonal patterns of rainfall and abundance within various...

Humid tropical forests have the highest rates of litterfall production globally, which fuels rapid nutrient recycling and high net ecosystem production. Severe storm events significantly alter patterns in litterfall mass and nutrient dynamics through a combination of canopy disturbance and litter deposition. In this study, we used a large-scale long-term manipulation experiment to explore the separate and combined effects of canopy trimming and litter deposition on litterfall rates and litter nutrient concentrations and content. The deposition of fine litter associated with the treatments...

Hurricanes, cyclones, or typhoons are intense and broad-scale disturbances that affect many island and coastal ecosystems throughout the world. We summarize the findings of the articles that compose this special issue of Forest Ecology and Management, which focuses on a manipulative experiment (the Canopy Trimming Experiment, CTE) that simulates two key aspects of hurricane effects in a wet tropical forest. Although previous studies of tropical and subtropical forests have documented changes resulting from hurricanes, it is not clear which of the two simultaneously occurring direct effects...

To date, it is not clear which are the factors that most influence tropical forest recovery from hurricanes.Increased canopy openness and increased detritus (debris) deposition are two of the most likely factors,but due to their simultaneous occurrence during a hurricane, their relative effects cannot be separated without a manipulative experiment. Hence, in the Luquillo Experimental Forest (LEF) of Puerto Rico, the Luquillo Long-Term Ecological Research Program (LTER) has undertaken experimental manipulations in replicated 30 _ 30 m plots to simulate the major effects of hurricane...

Most research exploring the relationship between soil chemistry and vegetation in Alaskan Arctic tundra landscapes has focused on describing differences in soil elemental concentrations (e.g. C, N and P) of areas with contrasting vegetation types or landscape age. In this work we assess the effect of landscape age on physico-chemical parameters in organic and mineral soils from two longterm research sites in northern Alaska, the Toolik Lake and Imnavait grids. These two sites have contrasting landscape age but similar vegetation composition. We also used correlation analysis to evaluate if...