Treesearch

The magnitude, spatial patterns, and controlling factors of the carbon and water fluxes of terrestrial ecosystems in China are not well understood due to the lack of ecosystem-level flux observations. We synthesized flux and micrometeorological observations from 22 eddy covariance flux sites across China,and examined the carbon fluxes, evapotranspiration (ET), and water use efficiency (WUE) of terrestrial ecosystems at the annual scale. Our results show that annual carbon and water fluxes exhibited clear latitudinal patterns across sites. Both annual gross primary productivity (GPP) and...

In the Drylands of Northern China, such as the Loess Plateau region, a buffer zone of planted forests—a “Green Great Wall”—has been created in the last five decades. These government programs have often generated unintended environmental consequences, and have failed to achieve the desired benefits. Planted forests withhold erosion, dust storms and silting of streams but may reduce stream flow due to higher water use with serious consequences for water management. In spite of contrary expectations, afforestations improve regional climate conditions only insignificantly in the temperate...

While horizontal gradients of biodiversity have been examined extensively in the past, vertical diversity gradients (elevation, water depth) are attracting increasing attention. We compiled data from 443 elevational gradients involving diverse organisms worldwide to investigate how elevational diversity patterns may vary between the Northern and Southern hemispheres and across latitudes. Our results show that most elevational diversity curves are positively skewed (maximum diversity below the middle of the gradient) and the elevation of the peak in diversity increases with the elevation of...

Resource and logistical constraints limit the frequency and extent of environmental observations, particularly in the Arctic, necessitating the development of a systematic sampling strategy to maximize coverage and objectively represent environmental variability at desired scales. A quantitative methodology for stratifying sampling domains, informing site selection, and determining the representativeness of measurement sites and networks is described here. Multivariate spatiotemporal clustering was applied to down-scaled general circulation model results and data for the State of Alaska at...

Passive management to preserve endangered plant species involves measures to avoid anthropogenic disturbance of natural populations, but this approach may not sustain plants that require disturbance-maintained habitats. Active management is often necessary to maintain existing habitats or provide new habitats for endangered species recovery. Our objective was to examine the effects of two disturbances in floodplain forests, soil flooding and light availability, on survival, stem length, stem diameter and ramet production of endangered Lindera melissifolia (Walt.) Blume. We used a water...

Changes in forest carbon stocks can be detected through monitoring of deforestation (conversion of| forests to some other cover type), forest degradation (forests that remain forests), and/or reforestation| (restoration of forests). Techniques for monitoring deforestation and resultant changes to forest carbon| stocks are widespread and well published. However, techniques for monitoring degradation and| reforestation are relatively untested in developing countries despite their inclusion in current UNFCCC| REDD+ negotiations..

Understanding the distribution of key biotic elements of forest ecosystems is essential in contemporary forest management and in planning to meet future management needs. Habitat distribution (niche) models based on known occurrences provide geographical structure for such management as the environmental factors change. Bark beetles play critical roles in coniferous forest dynamics in western North America. Among these insects, Dendroctonus rhizophagus Thomas and Bright, which occurs in the Sierra Madre Occidental in Mexico, is unique in that it attacks only immature trees (Pinus spp.) and...

Global forests capture and store significant amounts of CO2 through photosynthesis. When carbon is removed from forests through harvest, a portion of the harvested carbon is stored in wood products, often for many decades. The United States Forest Service (USFS) and other agencies are interested in accurately accounting for carbon flux associated with harvested wood products (HWP) to meet greenhouse gas monitoring commitments and climate change adaptation and mitigation objectives. National-level forest carbon accounting has been in place for over a decade, but there is an increasing need...

This joint research project formed by Southern University, Louisiana State University, and the USDA Forest Service focuses on applying nanotechnology in forest health and natural resource management. The targeted nanotechnology is derived from a new generation of renewable composite nano-material called Copper-Carbon Core-Shell Nanoparticles (CCCSNs), which have received increasing attention because of their low cost, unique stabilities, and demonstrated performance against Formosan termite and fungal diseases. This paper describes (1) the physical and chemical properties of CCCSNs and...

A growing body of evidence suggests that bark beetles detect and avoid release points of volatile compounds associated with nonhost species, and thus such nonhost volatiles may have potential utility in the management of bark beetles. We used a coupled gas chromatograph-electroantennographic detector (GC-EAD) to assay the olfactory sensitivity of the southern pine beetle, Dendroctonus frontalis Zimmermann, to volatiles from leaves and bark of eight species of nonhost angiosperm trees that are common in the range of D. frontalis. Tree species sampled were red maple (Acer rubrum L.),...