نتایج جستجو برای: vegetation understory
تعداد نتایج: 49366 فیلتر نتایج به سال:
Garlic mustard, an invasive exotic biennial herb, has been identified in the Upper Peninsula of Michigan, but is not yet widely distributed. We tested the effectiveness and impact of management tools for garlic mustard in northern hardwood forests. Six treatment types (no treatment control, hand-pull, herbicide, hand-pull/herbicide, scorch, and hand-pull/scorch) were applied within a northern h...
We compared three methods of sampling forest vegetation for their ability to reliably estimate changes in species richness, plant abundance, and overstory basal area and composition. Methods include the US Forest Service’s Forest Inventory and Analysis (FIA) method and two other methods being considered for use in monitoring National Parks in the Northern Great Lakes ecoregion. All methods were...
Forest decline is perceived as a threat to forest health in many regions of the world. The decline of red spruce in the mountains of the northeastern United States is one well-known example. We evaluated the impact of spruce decline by considering its effect on the prevailing gap dynamics. We compared plant composition, height growth, and indices of resource availability in gaps to the forest a...
Woodland caribou (Rangifer tarandus caribou) are sensitive to changes in understory vegetation resulting from forest harvesting and are, therefore, of special concern for foresters and habitat biologists. Effective management of this species requires reliable habitat inventories which, because of the large heterogeneous areas over which caribou range, can be costly. We used Landsat Thematic Map...
Thermal dependence of the enzymes SOD, CAT, and POD was investigated in leaves of Iris pumila plants inhabiting two contrasting light environments, a sun-exposed dune site and a woodland understory. At the same assay temperature, both the specific activity and the activation energy of SOD and CAT were higher in plants inhabiting vegetation shade than in those experiencing full sunlight. Convers...
In this study, the structurally heterogeneous canopy of a 12-ha plot in an old-growth Douglas-fir forest was analyzed using three-dimensional (3-D) canopy modeling, geographic information system (GIS), and spatial statistics. Using this approach, we were able to depict how species composition and spatial distribution affect the 3-D structure of canopies. We were also able to slice the canopy an...
The fragmentation of forest ecosystems is common in the northeastern United States (Cadenasso, 1997). Many studies have focused on the biotic factors of forest edges. These have shown that edge vegetation is different compositionally and structurally from forest interior vegetation (Brothers, 1992; Luken, 1991; Matlack, 1993; 1994). Steeper climactic gradients are created when trees are removed...
The amount of wood ash produced in power plants is increasing with increasing use of forest biomass in energy production. Wood ash can be recycled as fertilizer especially in boreal peatland forests naturally rich in nitrogen. Improved nutrient availability and increases in soil pH can enhance microbial activities, decomposition of organic matter and greenhouse gas (GHG) emissions. We studied t...
The Chinese Loess Plateau region has long been suffering from serious soil erosion. Thus, large-scale afforestation has continued during the past decades in order to control soil erosion. Afforestation can dramatically alter nutrient cycles, affect soil-carbon storage, and change hydrology. However, it is unknown how afforestation influences species diversity of the soil seed bank and understor...
Indian forests provide a multitude of services to vast populations. Common human activities including livestock grazing, fuelwood extraction and burning have the potential to impact forest ecosystem structure and function. The effects of these activities on vegetation, ecology and soil properties were investigated in Bandipur National Park (BNP) in southern India. Data were collected from 200 s...
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