خيارات البحث
النتائج 61 - 70 من 175
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 [-]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 [-]Effect of long-term contrasting anthropogenic emission on ectomycorrhizal diversity of Scots pine stands in Poland
2002
Rudawska, M. (Polish Academy of Sciences, Kornik (Poland). Institute of Dendrology) | Leski, T. | Kieliszewska-Rokicka, B. | Staszewski, T.
Ectomycorrhizal types were quantified in soil cores taken from 0-5 cm horizon. Nine ectomycorrhizal types were distinguished on roots of pines grown close to the copper smelter, 17 on trees grown in vicinity of aluminium smelter versus 25 found on trees grown near phosphate fertilizer plant and from control trees. Molecular studies were performed to give a greater resolution of how emission from different sources influenced mycorrhizal fungal community of Scots pine
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 [-]Assessment of ozone air pollution injuries on forest vegetation in the Transalpine region of Lombardy (Italy) and Canton Ticino (Switzerland)
2002
Ballarin-Denti, A. (Universita Cattolica di Brescia, Brescia (Italy). Dip. Matematica e Fisica) | Bussotti, F. | Cozzi, A. | Krauchi, N. | Gerosa, G. | Schaub, M. | Skelly, J. M. | Tagliaferri, A.
Many previous studies evidenced very high levels of air pollution by ozone between the North Italy (Lombardy) and the Southern Switzerland (Canton Ticino). These levels are mostly attributed to the influence of the large urbanized area of Milan and to the urban and industrial settlements in the Po Valley. Recent researches revealed the existence of spread foliar ozone-like symptoms in many native plant species, both in the Swiss and in Italian sector. Experiments carried out in open top chambers in Canton Ticino allowed us to attribute the foliar symptoms to the ambient air pollution levels
اظهر المزيد [+] اقل [-]Diameter and diameter increment values of beech trees grown on permanent research plots with various stand densities, in the submountain vegetation tier
2002
Vosko, M. | (Forest Research Institute, Zvolen (Slovak Republic)) | Jezik, M. (Institute of Forest Ecology of Slovak Academy of Sciences, Zvolen (Slovak Republic))
The attention was focused on the diameter increment of beech timber forest growing on the partial plots with various stand density. The individual parts of the originally homogenous stand, were subjected to regeneration cutting of various intensity resulting in several partial plots. On the different partial plots we found different proportions of trees belonging to the individual diameter classes. We also found that the differences between the individual plots were statistically very significant. Beech is a tree species which is capable to continue creating considerable light increments even long after the stand opening
اظهر المزيد [+] اقل [-]The progress and perspectives of ILTER research in Poland
2002
Zalewski, M. (Polish Academy of Sciences, Warsaw (Poland). International Centre for Ecology)
The general conclusions of Warsaw ILTER meeting was that following ILTER philosophy, ecological processes integrity can be maintained on the basis of profound knowledge on the rate of changes, hierarchy of driving forces and resistance and resilience of ecosystems. To achieve such complex understanding of these processes there is a need , first to collect and analyze broad spectrum of data possibly standardized by methodology and next permanently exchange information with coordinators from other countries and regions. As a consequence the participants suggested to extend the initial number of 6 sites situated mostly at National Parks and MAB Biosphere Reserve by the new sites representing broader scope of ecosystems and wider range of its anthropogenic modifications. This should allow to define the regional hierarchy of factors deteriorating the ecological systems and create better scope for comparative studies for global environment
اظهر المزيد [+] اقل [-]Natural regeneration of Norway spruce ecosystems in the Krkonose mountains: conditions and constraints
2002
Cudlin, P. | (Academy of Sciences of Czech Republic, Ceske Budejovice (Czech Republic). Institute of Landscape Ecology) | Chmelikova, E. | Falta, V. | Gronsky, R. | Sera, B. | Polak, T.
Results on germination, growth and mortality of Norway spruce seedlings during period 1994-2000 in various types of soil cover were summarized and evaluated. The years 1992 and 1995 were recorded as high seed production years, while the year 2000 is considered as the low seed production year. In 1999 natural seedlings from various soil covers were examined for lateral root and root tip development. The results of germination and surviving of Norway spruce seedlings are discussed in relationship with the stage of the decline of Norway spruce ecosystems
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 [-]