خيارات البحث
النتائج 21 - 30 من 179
Long-term research in the forest ecosystems under the influence of Gabcikovo hydropower plant
2002
Oszlanyi, J. (Slovak Academy of Sciences, Bratislava (Slovak Republic). Institute of Landscape Ecology)
48 sites were chosen for the ecological research and monitoring in the area influenced by the Gabcikovo hydropower plant. Decrease and exceptional increase of groundwater level was the main factor, which was expected to cause abrupt and intensive changes in production-ecological parameters, in structure and composition of tree, shrub and herbaceous layers. In chosen sites measurements and observations started in 1987. Abrupt and intensive growth of the leaf area index and improvement of health condition of tree and shrub layer was observed
اظهر المزيد [+] اقل [-]Reindeer summer pastures and ultraviolet radiation (UV)
2002
Soppela, P. (University of Lapland, Rovaniemi (Finland). Arctic Centre) | Turunen, M. | Heiskari, U. | Forbes, B. | Aikio, P. | Magga, H. | Sutinen, M. L. | Ahman, B. | Helle, T. | Nieminen, M. | Kyro, E. | Lakkala, K. | Huttunen, S. | Uhlig, C.
The aim of the proposed research is to investigate the effects of UV-radiation on chemical composition, palatability and digestibility of summer pasture plants of reindeer. The studies are planned to be conducted in natural peatland ecosystems with (I) enhanced UV-B radiation, provided by UV-B lamps and (II) with UV-filtration experiments with the same plant species in reindeer pastures in the Lappi Reindeer Herding Cooperative in Eastern Finnish Lapland. The results will provide information about the effects of ambient and enhanced UV radiation on summer pastures of reindeer and can be used to evaluate their consequences on reindeer management
اظهر المزيد [+] اقل [-]Epiphytic lichens as air quality indicators in forest stands
2002
Mavsar, R. (Slovenian Forestry Institute, Ljubljana (Slovenia)) | Batic, F. | Jeran, Z.
An outline of the analyses of experimental material from the 2000 moss survey is given. It includes some selected areas in Central Russia, Bosnia, Bulgaria, Romania, Slovakia and Serbia. Applying this methodology to areas of Central and Eastern Russia, not yet covered by the European moss surveys, will significantly broaden our understanding of air pollution in Europe
اظهر المزيد [+] اقل [-]The ecophysiological indicators of air pollution stress of beech (Fagus sylvatica L.) in Zasavje area, Central Slovenia
2002
Kalpic, A.B. (Ecological Research and Industrial Cooperation, Velenje (Slovenia)) | Lasnik, C.R.: Simoncic, P.
Several investigations about air pollution impact on forests have been carried out in Slovenia during last thirty years, mainly using the Norway spruce (Picea abies [L.] Karst.) as the main bioindication species, but there is a lack of information about common beach (Fagus sylvatica L.) condition, the most important forest tree species in Slovenia and in Zasavje area. The assessment of air pollution effect on beech based on stress physiological indicators of foliage, macronutrients level in beech leaves and by assessment of crown defoliation was carried out altogether with necessary soils analyses of the selected beech stands. On the basis of all parameters it can be concluded that the worst condition of beech trees in Zasavje is due to high level of air pollution, mainly by sulphur dioxide and not by deficiency of macronutrients or unfavourable state of soils
اظهر المزيد [+] اقل [-]Effects of carbon dioxide and ozone on growth and biomass allocation in Pinus ponderosa
2002
Olszyk, D. (US EPA, St. Corvallis, (USA). Western Ecology Division) | Johnson, M. | Tingey, D. | King, G. | Storm, M. | Plocher, M.
The future productivity of forests will be affected by combinations of anthropogenic stresses including elevated atmospheric CO2 and O3. Because the productivity of forests, will be in part, determined by the growth of young trees, we evaluated the responses of Pinus ponderosa seedlings to ambient or elevated CO2 and/or high O3. Shoot growth and whole plant biomass were evaluated for seedlings growing under the CO2 and O3 treatments for 3 years in sun-lit mesocosms with ambient temperature and humidity. This study indicated the potential for CO2 but not O3 effects on Pinus ponderosa seedlings under realistic field conditions as used in this study
اظهر المزيد [+] اقل [-]Ectomycorrhizal associations in Norway spruce stands influenced by long lasting air pollution (Silesian Beskid Mountains, Poland)
2002
Rokicka-Kieliszewska, B. (Polish Academy of Sciences, Kornik (Poland). Institue of Dendrology) | Rudawska, M. | Staszewski, T. | Kurcynska, E. | Karlinski, L.
Norway spurce (Picea abies L.) is the dominating tree species in the Silesian Beskid Mountains. The mountain forests are under severe climatic conditions, such as low temperatures, short growing season, strong winds, high annual precipitation, a long-time snow cover. The forests have been exposed also for about half century to gaseous and dust pollutants emitted by large industrial centres in the Czech Republic, Germany and Poland. Anthropogenic impacts may influence negatively the growth of tree fine roots, can develop ectomycorrhizas and alter the communities of ectomycorrhizal fungi and other microorganisms in soil. Ectomycorrhizal communities at the both forest sites were dominated by the same two morphotypes, which were further studied using the PCP-RFLP analysis for identification of the fungal species
اظهر المزيد [+] اقل [-]Long-term effect of alkaline air pollutants on forest ecosytems
2002
Caboun, V. | Mindas, J. | Priwitzer, T. | Pavlenda, P. | Istona, J. | Pavlendova, H. (Forest Research Institute, Zvolen (Slovak Republic))
The effect of alkaline air pollutants appears on 98% of the area of forests in Slovakia. Despite a local impact of magnesite air pollutant type is very significant as to the degree and extent of damage. Despite enormous efforts of magnesite plants only a low reduction of dust fallout was reached. While in the years 1978-1979 emission of Mg dust reached 7396.5 tons and emission of SO2 1133.5 tons, in the years 1990-1991 respective figures were 1174.5 tons of Mg dust and 1114 tons of SO2. It means that the amount of emitted SO2 has not changed but the amount of emitted dust has dropped 6.5 times. On the basis of research results the whole attacked territory was divided into four zones of endangerment and there were tested various reclamation and revitalization measures successfully
اظهر المزيد [+] اقل [-]Effect of increasing ozone and carbon dioxide on photosynthetic and related biochemical properties of two silver birch clones during three years of exposure
2002
Riikonen, J. (Finnish Forest Research Institute, Suonenjoki (Finland). Suonenjoki Research Station) | Holopainen, T. | Oksanen, E. | Vapaavuori, E.
Under elevated CO2 photosynthesis was 15-50% higher than in chamber controls depending on the weather conditions of the growing seasons. When measured at 360 ppm CO2 both elevated CO2 and elevated CO2 + O3 treatments decreased net photosynthesis, stomatal conductance and also transpiration, indicating downregulation of photosynthesis at elevated CO2
اظهر المزيد [+] اقل [-]Forests health status as the result of environmental impacts and forestry interventions
2002
Hocevar, M. | Mavsar, R. | Kovac, M. (Slovenian Forestry Institute, Ljubljana (Slovenia))
The analysis of the latest results along with the change analysis reveals that the conditions of Slovenia's forest are considerably stable and that the process of decline has not progressed with the intensity, that had been predicted in the early eighties. Quite favourable conditions are due to prompt actions (selection and sanitary cutting) in the field
اظهر المزيد [+] اقل [-]Is microbial population associated to ectomycorrhized roots of Norway spruces in Krkonose National Park influenced by forest decline?
2002
Martinotti, M.G. (University of Piemonte Orientale, Novara (Italy)) | Avidano, L. | Fracchia, L.
Investigations on the bacterial communities associated to ectomycorrhized roots of seedlings from three stands with different degrees of regeneration decline (high, intermediate and low) and from seedlings grown on monoliths obtained from the very same stands have been carried out. The results suggest that forest decline does not influence bacterial biomass associated to seedlings roots but induce a clustering of specific bacterial species adapted to the different degree of forest decline
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