Treesearch

Intensive forestry has resulted in considerable increases in aboveground stand productivity including foliar and belowground biomass which are the primary sources of soil organic matter. Soil organic matter is important for the maintenance of soil physical, chemical and biological quality. Additionally, sequestering carbon (C) in soils may provide a means of mitigating increasing atmospheric carbon dioxide concentrations. In this study, we examined soil C and nitrogen (N) contents and stabilization in 12-year-old, intensively managed sweetgum (Liquidambar styraciflua L.) and loblolly pine...

This research was conducted to develop relationships among evapotranspiration (ET), percolation (PERC), groundwater discharge to the stream (GWQ), and water table fluctuations through a modeling approach. The Soil and Water Assessment Tool (SWAT) hydrologic and crop models were applied in the Big Sunflower River watershed (BSRW; 7660 km2) within the Yazoo River Basin of the Lower Mississippi River alluvial plain. Results of this study showed good to very good model performances with the coefficient of determination (R2) and Nash- Sutcliffe efficiency (NSE) index from 0.4 to 0.9, respectivel...

Given the importance of biological corridors, it is necessary to evaluate their fauna especially those species are bioindicators of habitat quality, to determine patterns and extent of community diversity and how such factors reflect the level of conservation within and among green corridors in general. We investigated how selected landscape features within the Paso del Istmo, located in the Department of Rivas, Nicaragua, are influencing avian diversity and how key groups are providing clues to habitat quality. We recorded 8703 detections of 168 avian species using fixed-radius point...

Precipitation and temperature are important drivers of soil respiration. The role of moisture and temperature are generally explored at seasonal or inter-annual timescales; however, significant variability also occurs on hourly to daily time-scales. We used small (1.54 m2), throughfall exclusion shelters to evaluate the role soil moisture and temperature as temporal controls on soil CO2 efflux from a humid tropical forest in Puerto Rico. We measured hourly soil CO2 efflux, temperature and moisture in control and exclusion plots (n = 6) for 6-months. The variance of each time series was...

Designing woody fuel sampling methods that quickly, accurately and efficiently assess biomass at relevant spatial scales requires extensive knowledge of each sampling method's strengths, weaknesses and tradeoffs. In this study, we compared various modifications of three common sampling methods (planar intercept, fixed-area microplot and photoload) for estimating fine woody surface fuel components (1-, 10-, 100-h fuels) using artificial fuelbeds of known fuel loadings as reference. Two modifications of the sampling methods were used: (1) measuring diameters only and both diameters and...

The association between humans and their environments is highly interactive, with humans bound to the landscapes and landscapes subject to the actions of humans. Sense of place is a concept used to describe the relationships that exist, bonds that form, and the meanings that humans ascribe to landscapes. This article builds on pre- vious qualitative research using public participation geographic information systems (PPGIS) to develop an alternative and efficient methodology to spatially represent place. The approach integrates participatory mapping procedures within a focus group format....

Ridges within the lower montane rain forests (sensu Beard) of the Caribbean Basin are dominated by Dacryodes excelsa, a tree species known as tabonuco in Puerto Rico and gommier in the Lesser Antilles. Periodially, hurricanes traverse the islands causing changes in structure, species composition, and dynamics of forests. The chronology of post-hurricane vegetation change from 1946 to 2010 on a 0.4 ha ridge plot approximately 380 m in elevation in the Luquillo Experimental Forest of northeastern Puerto Rico showed: (1) defoliation, breakage, and uprooting by wind accompanied by immediate...

Tropical plantations are considered a viable option to sequester carbon on abandoned agricultural lands, but implications of tree species selection for overall greenhouse gas budgets on plantations have been little studied. During three wet seasons, we investigated the influence of nine tree species on soil pH, temperature (ST), bulk density (BD), moisture content water filled pore space (WFPS), and greenhouse gas fluxes in diverse forest sites and monoculture plantation plots. All sites were on clay-rich soils of the Barreiras formation, in east-central Amaz^onia, Brazil. We found that ST...

Urbanization destroys or modifi es native habitats and creates new ones with its infrastructure. Because of these changes, urban landscapes favor non-native and native species that are generalists. Nevertheless, cities reveal a great variety of habitats and species, and, especially in temperate cities, the diversity of vascular plants and birds can be higher than in the surrounding landscapes. The actual occurrence of a species, however, depends on habitat availability and quality, the spatial arrangements of habitats, species pools, a species’ adaptability and natural history, and site...