نتایج جستجو برای: shrub canopy
تعداد نتایج: 19636 فیلتر نتایج به سال:
Boreal forests often have a dense understorey of ericaceous dwarf shrubs with ecological adaptations that contrast those the canopy-forming trees. It is therefore important to quantify contributions by ecosystem processes and disentangle shrub- tree-driven responses climatic factors. We quantified soil respiration driven pine canopy shrub over 3 years, using factorial root exclusion removal exp...
In the southern Appalachian mountains Rhododendron maximum L. (R.m.) is the dominant subcanopy evergreen species. Approximately 30 million hectares of the southern Appalachian mountains are occupied by R.m. This subcanopy evergreen shrub forms extensive thickets, near streams and on north slopes, reaching a height of 3-6 m. On north-facing slopes these thickets form a mosaic of -40% cover. Ther...
Seventeen exclosures were built by the New Zealand Forest Service within Urewera forests over the period 1961-68 to exclude ungulates. Forest structure and species composition inside and outside these exclosures were compared in 1980-81. Some relatively shade tolerant species such as the fern Asplenium bulbiferum, the liane Ripogonum scandens, the sub-canopy shrubs Geniostoma ligustrifolium and...
--The habitat requirements of open nesting birds were examined in 19, five hectare, plots arranged along an altitudinal gradient in western Montana. Seven, mature forest birds were examined in detai 1. Percent shrub and low canopy cover {0.5-1.5m), mid-canopy cover {8-25m), and the number of large diameter stems {25-50 em dbh) were of major importance to this avian co11111unity. Increased avian...
We hypothesized that biodiversity improves ecosystem functioning and services such as nutrient cycling because of increased complementarity. We examined N canopy budgets of 27 Central European forests of varying dominant tree species, stand density, and tree ∗Corresponding author: [email protected] †University of Berne, Institute of Geography, Hallerstrasse 12, 3012 Berne, Switzerland ‡Fr...
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...
Canopy analysis was carried out in order to classify the differences between vegetation types at the Szárazvölgy flotation sludge reservoir. Supervised classification methods were used to distinguish 8 vegetation types based on the spectral properties of the area: forest (Quercus sp.), young deciduous forest, reed (Phragmites sp.) and aquatic plants, false indigo (Amorpha fruticosa), Australian...
Studies of the bidirectional behavior of forest canopy have shown that the total reflectance of a forest canopy is the combination of illuminated and shaded components of the tree crown as well as the background. The vegetation background (soil/moss/grass/shrub in forests) is a recognized problem that limits the accuracy of satellite-estimated forest LAI. Previous LAI validation efforts have re...
BACKGROUND Molecular clocks drive oscillations in leaf photosynthesis, stomatal conductance, and other cell and leaf-level processes over ~24 h under controlled laboratory conditions. The influence of such circadian regulation over whole-canopy fluxes remains uncertain; diurnal CO2 and H2O vapor flux dynamics in the field are currently interpreted as resulting almost exclusively from direct phy...
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