خيارات البحث
النتائج 1 - 10 من 14
Direct and Indirect effects and the Long-term Risks of Air Pollution on Forest Ecosystems:
1993
Skelly, J.M. (Pennsylvania State University, University Park (USA))
Tropospheric ozone is the most important single air pollutant of importance to forests in eastern United States. Both broadleaf and needled trees may suffer premature foliar senescence following even low ozone exposure years. Genetic sensitivity within species is likewise prevalent.
اظهر المزيد [+] اقل [-]Indirect effects and the Long-term Risks of Air Pollution on Eastern North American Temperate Forest Ecosystems: Insect Outbreaks
1993
Chappelka, A.H. (Auburn University, Alabama (USA). School of Forestry)
Air pollutants cause subtle changes in natural resistance that can prediscope plants to insect attack. The majority of reports in the area of plant-pollutant-insect interactions have been correlative in nature. In the last ten years, there has emerged a growing body of literature, the vast majority with herbaceous crops, reporting on cause-effect relationships among insects and their hosts.
اظهر المزيد [+] اقل [-]Indirect effects and the Long-term Risks of Air Pollution on Eastern North American Forest Ecosystems: Pathological Problems
1993
Chappelka, A.H. (Auburn University, Alabama (USA). School of Forestry)
Air pollutants such as ozone may affect tree host-pathogen interactions by altering plant tissue susceptibility, plant resistance, pathogen virulence and inoculum density. Ozone has been shown to weaken trees in natural stands and increase their susceptibility to invasion by plant pathogens, such as Heterobasidion annosum. Ozone has also been shown to enhance disease development by fungi that are normally saprophytic in nature.
اظهر المزيد [+] اقل [-]Effects of Acidic Deposition on Calcium Nutrition of Spruce/fir Forests in the Eastern U.S.: Implications for Physiological Processes, Growth, and Climate Interactions
1993
McLaughlin, S.B. (Oak Ridge National Laboratory, Oak Ridge, TN (USA))
Calcium avaiability to forests has been shown to be reduced by acidic deposition in several ways including: increased leaching from foliage, increased leaching from soils, and decreased availability from poorly buffered soils when aluminium is mobilized. Studies documented that acidic deposition has altered the growth and vigour of red spruce during the past three decades by changing calcium availability.
اظهر المزيد [+] اقل [-]Potential Impacts of Climate Change on Forests in China
1993
Deying Xu (Chinese Academy of Forestry, Beijing (China))
Experimental research on the physiology of tree seedlings under simulated climate and doubled carbon dioxide can rarely be extrapolated to grown forests. Climatological research has demonstrated a warming trend in the north and a cooling trend in the south of China. However, the changing climate has not caused the death of forests. Projecting the impact of climate change on forest distribution and growth using current GCMs seems to be the only method available.
اظهر المزيد [+] اقل [-]Direct and Indirect effects and the Long-term Risks of Air Pollution on Forest Ecosystems in the Mediterranean Region
1993
Innes, J.L. (Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf (Switzerland))
Most concern about the effects air pollution has been directed towards central and northern Europe, although considerable damage has been attributed to air pollution in the Mediterranean countries. The damage is mostly in the vicinity of point sources and can usually be related to specific pollutants such as sulphur dioxide and hydrogen fluoride.
اظهر المزيد [+] اقل [-]Socio-economic assessment of global change and air pollution-related forestry damage
1993
de Steiguer, J.E. (USDA Forest Service, Raleigh, North Carolina (USA))
Information on potential forestry losses seems to be crucial to government officials that they can properly assess the costs and benefits of limiting pollution and greenhouse gas emissions. However very few socio-economic assessments of potential losses have been completed.
اظهر المزيد [+] اقل [-]Effects of climate change and atmospheric pollution on forest ecosystems in eastern North America
1993
Hall, J.P. (Forestry Canada, Ottawa (Canada))
Climate change will be the major impact on all forests, included increased risk of large-scale fires, enhanced susceptibility to insects and diseases. Direct effects of air pollution on vegetation include damage to protective surface structures, disturbance of photosynthesis.
اظهر المزيد [+] اقل [-]Pedologic and nutritional aspects of enhanced carbon-dioxide storage in forest ecosystems
1993
Huettl, R.F. (Forestry Dept. Kali and Salz AG, Kassel (Germany))
Enhanced forest growth in combination with relatively high Nitrogen deposition may result in further pedologic and nutritional changes and an even greater destabilisation of forest ecosystems.
اظهر المزيد [+] اقل [-]Climate Change and Forest Ecosystems - an Overview
1993
Kraeuchi, N. (Swiss Federal Institute of Technology, Zurich (Switzerland). Department of Forest and Wood Research)
Climate change must be considered an ecological and socio-economic threat. We have to support any measures that are combating climate change. It is currently unknown which climate scenario will come true, and therefore very important to maintain the biological diversity of the forest ecosystems for a wide variety of possible development.
اظهر المزيد [+] اقل [-]