نتایج جستجو برای: shrub canopy
تعداد نتایج: 19636 فیلتر نتایج به سال:
Satellite photo-comparisons indicate extensive expansion of alder (Alnus) shrubs since 1968 within tundra ecotones near Kharp in northwest Siberia. Field observations reveal that nearly all expansion occurred on exposed circles in patterned ground. We mapped the location of alders and circles and measured surface organic thickness, mineral soil thickness, nearsurface soil temperature, shrub hei...
Most studies on frugivorous bat assemblages in secondary forests have concentrated on differences among successional stages, and have disregarded the effect of forest management. Secondary forest management practices alter the vegetation structure and fruit availability, important factors associated with differences in frugivorous bat assemblage structure, and fruit consumption and can therefor...
Vegetation structure influences habitat selection for woodland birds and is a key component determining habitat quality. At Scandlaser 2003, and elsewhere, we have demonstrated the application of airborne LiDAR data for organism-habitat modelling. In this paper we review the results of our pilot study which focussed on two species of tits, Great Tit Parus major and Blue Tit Parus caeruleus, in ...
Thirty nests of Hammond’s (Empidonax hammondii) and 88 nests of Pacificslope (E. difficilis) Flycatchers were located in different-aged Douglas-fir (Pseudotsuga menziesii)/tanoak (Lithocarpus densiflorus) dominated forests at 12 study sites in northwestern California during the breeding seasons of 1984, 1985, 1987, and 1988. In contrast to Pacificslope Flycatchers, Hammond’s used nest trees tha...
Juniper ; encroachment into shrub steppe and grassland systems is one of the most prominent changes occurring in rangelands of western North America. Most studies on juniper change are conducted over small areas, although encroachment is occurring across large regions. Development of image-based methods to assess juniper encroachment over large areas would facilitate rapid monitoring and identi...
The exotic shrub glossy buckthorn (Frangula alnus) is a great concern among forest managers because it invades both open and shaded environments. To evaluate if buckthorn grows similarly across light environments, and if adopting different shapes contributes to an efficient use of light, we compared buckthorns growing in an open field and in the understory of a mature hybrid poplar plantation. ...
AB%rKA(:f.-Canopy gaps in southern Appalachian mixed-oak forests were assessed foxthe effects of topographic, gap and stand variables on density of wood seedlings. Seedling density was significantly correlated with percent slope and positively with gap age (l-5 yr). Density varied substantially among topographic positions and increased with gap size. Specirs richness decreased ovt’itime and inc...
Global mapping of the vegetation clumping index is attempted for the first time using multi-angular POLDER 1 data based on a methodology that has been demonstrated to be applicable to Canada’s landmass. The clumping index quantified the level of foliage grouping within distinct canopy structures, such as tree crowns, shrubs, and row crops, relative to a random distribution. Vegetation foliage c...
Use and management of jatropha residue is currently an important global issue for attaining sustainability in biofuel production from Jatropha curcas on wastelands. Perhaps, knowledge about the decomposition characteristics and nutrient release pattern from jatropha residues amended soils are lacking. Thus, the objective of present research was to characterize the carbon (C) and nitrogen (N) mi...
We used logistic regression to identify environmental and management history factors associated with blue oak (Quercus douglasii) sapling recruitment. Recent canopy gaps caused by natural mortality or clearing were positively associated with sapling recruitment. Plots with very high or low levels of tree canopy cover were less likely to have saplings than those with intermediate canopy cover le...
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