خيارات البحث
النتائج 101 - 110 من 184
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 [-]Foreign tree species cultivated in the emission damaged area of the ore mountains
2002
Paul, M. (Saxon State Institute for Forestry, Pirna/OT Graupa (Germany). Department of Genetics and Breeding)
The paper presents forest damage in Saxony, silvicultural treatment and the choice of tree species, base of the choice of tree species for areas damaged by air pollutants and solving the problems only on interdisciplinary basis
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 [-]Change analyses of forest health condition development in Ziar nad Hronom region influenced by aluminium plant
2002
Bucha, T. | Mankovska, B. (Forest Research Institute, Zvolen (Slovak Republic))
Forest health condition was evaluated on 111 terrestrial permanent monitoring plots. Image classification for the whole region was done by using regression equation between data from the terrestrial survey and digital value of original and derived synthetic bands of Landsat TM. It was found that synthetic channels give better result than original bands. The change analysis was carried out by the method of image diffferences in image pairs. Output images were standardized and than reclassified into 6 classes. It was found that difference of vegetation indexes between two years gives better result than simple difference between two independent classified images of forest condition
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 [-]Discussion of the effects of N with and without acidified S on a sitka spruce ecosystem after 5 years treatment
2002
Sheppard, L.J. | (CEH Edinburgh Bush Estate, Edinburgh (United Kingdom)) | Crossley, A. | Ingleby, K. | Carfrae, J. | Harvey, F. | Kennedy, V.
Significant differences in the effects of N alone compared with NS Acid have been found with respect to eutrophication and acidification. N alone had no effect on the pleurocarpous mosses, whereas NS Acid caused their death within 2 years. Both treatments enhanced stem area increment and N alone also doubled fine root growth. By contrast NS Acid treatments increased litterfall in a a dose response fashion
اظهر المزيد [+] اقل [-]Yellowing of the Norway spruce stands in Central Europe
2002
Sramek, V. | Lomsky, B. (Forestry and Game Management Research Institute, Prague (Czech Republic))
Yellowing of trees with current year needle-class remaining green shows typical symptoms of magnesium deficiency. The chemical analysis proved severe deficiency of magnesium and mild deficiency of calcium in needles and forest soils indeed. This corresponds to the new forest decline as observed in the 1970s and the 1980s in some regions in Germany and France. Other contributing factor breaking out yellowing at that extent at particularly short time is not known. The problem is even increasing, because yellowing has recently appeared also in other mountain localities in Central Europe even though in smaller scale
اظهر المزيد [+] اقل [-]Conditions of natural regeneration of Norway spruce ecosystems in the Krkonose mountains
2002
Cudlin, P. (Academy of Sciences of the Czech Republic, Ceske Budejovice (Czech Republic). Institute of Landscape Ecology) | Godbold, L. | Bonifacio, E. | Egli, S. | Fritz, H. W. | Chmelikova, E. | Kowalik, P. | Martinotti, M. G. | Moravec, I. | Nicolotti, G. | Zanini, E.
The aim of the international EU project was to characterize the status, conditions, and constraints for natural regeneration of Norway spruce (Picea abies [L.] Karst.) ecosystems in different stage of forest decline on three permanent research plots in the Giant Mts., to assess whether the biotechnological measures are necessary to support a natural regeneration at each plot. There were not ascertained any fundamental differences in basic soil types of three permenent research plots. No significant differences were observed in diversity of fungal and bacterial rhizospheric populations, including ectomycorrhizal symbionts
اظهر المزيد [+] اقل [-]Evaluation of environmental impact on Pinus mugo Turra as bioindicator in Subalpine belt of Julian Alps in Slovenia
2002
Batic, F. (University of Ljubljana, Ljubljana (Slovenia). Biotechnical Faculty) | Mavsar, R. | Rozman, A. | Sircelj, H. | Simoncic, P. | Turk, B.
Determination of the streses operating on a forest ecosystem demands the use of several bioindication methods. Air quality indicators were assessed from an inventory of forest decline based on the assessment of tree crowns and lichens. Photosynthetic pigments, ascorbic acid and major macro nutrients were studied in mountain pine (Pinus mugo Yurra) needles as indicators of physiological and biochemical stress. Analyses were carried out at selected forest plots and transects in predominantly unpolluted areas within Triglav National Park, Julian Alps, Slovenia. It was assumed that air pollutant input in forest ecosystems is of two kind, e.g. local from the air pollutin sources in the valleys on the North-West part of tha national park and transboundary source at high altitudes
اظهر المزيد [+] اقل [-]Nitrogen budget on a limestone site in the Austrian Alps
2002
Herman, F. (Institut fur Immissionsforschung und Forstchemie, Vienna (Austria). Bundesamt und Forschungscentrum fur Wald) | Smidt, S. | Englisch, M. | Feichtinger, F. | Gerzabek, M.: Haberhauer, G. | Jandl, R. | Kalina, M. | Zechmeister-Boltenstern, S.
While nitrogen input exceeded the critical loads of the WHO (1995), nitrogen deficiency and nutrient imbalances were verified by needle analyses. The atmospheric input of inorganic nitrogen was higher than the nitrogen output in 50 cm soil depth. A tracer experiment with 15N helped to prove that not more than half of the applied nitrate could be discharged. This allows the conclusion that nitrogen is stored in the system and that the site cannot yet be said to be saturated with nitrogen. The same result was also obtained by modelling
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