نتایج جستجو برای: land fire
تعداد نتایج: 158578 فیلتر نتایج به سال:
One important area for which little experimental evidence is available is the snowgrass country. There is a strong body of opinion that in the snowgrass the combined effects of fire and grazing have been responsible for deterioration in vegetative cover and stability. It seems likely that changes in the boundari~s between the snowgrass and fescue communiti~s have been due to, or aggravated by, ...
Vegetation burning is a global environmental threat that results in local ecological, economic and social impacts but also has large-scale implications for global change. The burning is usually a result of interacting factors such as climate, land use and vegetation type. Despite its importance as a factor shaping ecological, economic and social processes, countries highly vulnerable to climate...
Fire is well recognized as a key Earth system process, but its causes and influences vary greatly across spatial and temporal scales. The controls of fire are often portrayed as a set of superimposed triangles, with processes ranging from oxygen to weather to climate, combustion to fuel to vegetation, and local to landscape to regional drivers over broadening spatial and lengthening temporal sc...
Our objective was to infer the climate drivers of regionally synchronous fire years in dry forests of the U.S. northern Rockies in Idaho and western Montana. During our analysis period (1650-1900), we reconstructed fires from 9245 fire scars on 576 trees (mostly ponderosa pine, Pinus ponderosa P. & C. Lawson) at 21 sites and compared them to existing tree-ring reconstructions of climate (temper...
THE colony of Hong Kong occupies a land area of 398k square miles. The total population at end of 1964 was estimated to be 3,739,900, 85 per cent. being concentrated in the urban areas of Hong Kong Island and Kowloon. On the basis of language and place of origin about 98 per cent. could be described as Chinese. Thus Chinese custom and traditions predominate in Hong Kong. One such custom is to d...
Wildfire suppression expenditures on national forest land have increased over the last 35 years, exceeding US$l billion in 2000 and 2002. These increases in expenditure have been attributed, in part, to a century of aggressive wildfire suppression, resulting in a buildup of fuel on the nation's forests. The efficiency of the current incentive structure faced by Forest Service fire managers is a...
National Park Service policy directs that more natural conditions be restored to giant sequoia groves, which have been altered by a century of fire exclusion. Efforts to find a reasonable and practical definition of ‘‘natural’’ have helped drive scientists and land managers to use past grove conditions as reference conditions for restoration. Extensive research aimed at determining reference co...
Spatially explicit forecasts of large wildland fire probability and suppression costs for California
In the last decade, increases in fire activity and suppression expenditures have caused budgetary problems for federal land management agencies. Spatial forecasts of upcoming fire activity and costs have the potential to help reduce expenditures, and increase the efficiency of suppression efforts, by enabling them to focus resources where they have the greatest effect. In this paper, we present...
Environmental regulations frequently mandate the use of "best available" science, but ensuring that it is used in decisions around the use and protection of natural resources is often challenging. In the Western US, this relationship between science and management is at the forefront of post-fire land management decisions. Recent fires, post-fire threats (e.g. flooding, erosion), and the role o...
The importance of fire in the creation and maintenance of mesic grassland communities is well recognized. Improved understanding of how grasses--the dominant clade in these important ecosystems--will respond to alterations in fire regimes is needed in the face of anthropogenically driven climate and land-use change. Here, we examined how grass communities shift in response to experimentally man...
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