نتایج جستجو برای: canopy cover

تعداد نتایج: 122030  

2000
William P. Kustas John H. Prueger Jerry L. Hatfield Kalia Ramalingam Lawrence E. Hipps

For many natural and agricultural landscapes, vegetation partially covers the ground surface, resulting in significant variations in soil heat flux between interspace areas and underneath vegetation. This is particularly apparent in arid and semiarid regions where vegetation cover is low and clustered or ‘clumped’ with large areas of exposed soil. Surface heterogeneity presents significant chal...

Forest fragmentation results in a loss of forest interior and an increase in edge habitat. We studied how understorey bird community composition and habitat variables changed along an edge-to-interior gradient in a 1248-ha lowland rainforest patch in peninsular Malaysia. Birds and environmental variables such as vegetation structure and litter depth were detected within a 25-m radius of each of...

2015
Elizabeth A. Roznik Sarah J. Sapsford David A. Pike Lin Schwarzkopf Ross A. Alford

Natural disturbances can drive disease dynamics in animal populations by altering the microclimates experienced by hosts and their pathogens. Many pathogens are highly sensitive to temperature and moisture, and therefore small changes in habitat structure can alter the microclimate in ways that increase or decrease infection prevalence and intensity in host populations. Here we show that a redu...

2000
N. A. Jackson

Rainfall interception losses from an agroforestry system in semi-arid Kenya comprising Grevillea robusta and maize were measured over a period of 33 months. These measurements showed that interception was slightly higher (10.2%) under trees with no maize understorey, than in the intercropped treatment (9.8%), and was directly related to the degree of tree canopy cover. Interception estimates us...

2005

We used snow fences and small (1m) open-topped fiberglass chambers (OTCs) to study the effects of changes in winter snow cover and summer air temperatures on arctic tundra. In 1994, two 60m long, 2.8m high snow fences, one in moist and the other in dry tundra, were erected at Toolik Lake, Alaska. OTCs paired with unwarmed plots, were placed along each experimental snow gradient and in control a...

2005
K. F. HUEMMRICH

Monthly measurements of leaf area index (LAI) and the fraction of absorbed photosynthetically active radiation (fAPAR) taken at approximately monthly intervals were collected along three 750 m transects in a Kalahari woodland near Mongu in western Zambia. These data were compared with MODIS NDVI (MOD13, Collection 3) and MODIS LAI and fAPAR products (MOD15, Collection 3) over a 2 year period (2...

2016
Anne C. S. McIntosh S. Ellen Macdonald Sylvie A. Quideau

Understory plant communities play critical ecological roles in forest ecosystems. Both above- and below-ground ecosystem properties and processes influence these communities but relatively little is known about such effects at fine (i.e., one to several meters within-stand) scales, particularly for forests in which the canopy is dominated by a single species. An improved understanding of these ...

2004
Timothy N. McPherson Michael J. Brown Steven J. Burian

Describing urban terrain and land use/land cover (LULC) characteristics accurately is an essential element in environmental modeling, assessment and management. Urban terrain and LULC information are especially important in meteorological modeling applications, such as simulations of atmospheric flow over cities, defining surface energy budgets, and fate and transport studies of urban contamina...

2012
David M. Williams Amy Dechen Quinn William F. Porter

Advances in animal tracking technologies have reduced but not eliminated positional error. While aware of such inherent error, scientists often proceed with analyses that assume exact locations. The results of such analyses then represent one realization in a distribution of possible outcomes. Evaluating results within the context of that distribution can strengthen or weaken our confidence in ...

2013
Huifeng Hu Benjamin O. Knapp G. Geoff Wang Joan L. Walker

We installed a field experiment to support the development of protocols to restore longleaf pine (Pinus palustris Mill.) to existing mature loblolly pine (P. taeda L.) stands at Camp Lejeune, NC. Seven canopy treatments included four uniform and three gap treatments. The four uniform treatments were defined by target residual basal area (BA) [control (uncut), BA9, BA4.5, and BA0 (clearcut) m2/h...

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