Refinar búsqueda
Resultados 41-50 de 184
Effects of preparatory stands on forest site restoration
2002
Remes, J. | Podrazsky, V. (Czech University of Agriculture, Prague (Czech Republic). Faculty of Forestry)
The main aims of the preparatory stands in air pollution areas are growth development, successfull dynamics of the plants and fast creation of the stand microclimate with favourable effect on soil conditions. This process is documented by height and diameter increment. The results confirm different growth dynamics of the particular species. Larch is the species with the best growth dynamics of selected species on experimental plots. On the other hand, beech is the worst species for reforestation in this condition. One of the causes could be damage by frost
Mostrar más [+] Menos [-]Forms - an integrated forest monitoring system in Denmark
2002
Bastrup-Birk, A. | Johannsen, V.K. (Centre of Forest, Landscape and Planning, Hoersholm (Denmark))
A FORest Monitoring System (FORMS) has been implemented in Denmark in order to gain and deliver knowledge and information for operational and strategic decisions concerning nature and environment. FORMS integrate four national monitoring programmes. Forest condition monitoring is performed on 52 permanent plots distributed on a 16 x 16 km grid. FORMS gives a systematic and representative assessment of the resources in and development of the forests in Denmark, includes the monitoring of important processes in the forest ecosystem and follows the use of forest for recreational purposes
Mostrar más [+] Menos [-]Response of subarctic tree seedlings to solar UV radiation
2002
Turunen, M. (University of Lapland, Rovaniemi (Finland). Arctic Centre) | Suttinen, M. L. | Derome, K. | Norokorpi, Y. | Lakkala, K.
The response of Betula pubescens Ehr., B. pendula Roth and two provenances of Pinus sylvestris L. to solar ultraviolet radiation were investigated in a UV exclusion field experiment during the 1997-1999 growing seasons in Finnish Lapland. The seed-grown seedlings were grown under UV-B exclusion and UV-B/UV-A exclusion as compared to control treatment and ambient plants. The only significant impacts of UV exclusion were found in P. sylvestris provenance Enontekio. Longer-term field studies are needed to detect the cumulative characteristics of the UV responses
Mostrar más [+] Menos [-]Heavy metals in Hypnum cupressiforme collected in the surroundings of oil plants in Ploiesti and Slovnaft
2002
Oprea, C. D. (FLNP, Dubna (Russia)) | Frontasyeva, M. V. | Pavlov, S. S. | Florek, M. | Mankovska, B. | Mihul, A. | Timofte, L.
The terrestrial moss Hypnum cupressiforme was collected in the surroundings of oil plant Slovnaft (Slovakia) and oil industry in Ploiesti (Romania) to monitor heavy metal atmospheric deposition. A comparative evaluation of heavy metal atmospheric deposition recorded at the two locations versus a background area in Europe as Norway is presented. The highest concentrations were observed for V, Cr, Fe, Co, Ni and As at Ploiesti and for V, Cr, Fe, Co, and Ag at Slovnaft. This moss is very useful as biomonitoring organism to indicate and characterize deposition of atmospheric pollutants nearby oil plants
Mostrar más [+] Menos [-]Leaf morphology and gas exchange in holm oak (Quercus ilex L.) trees in different environments
2002
Lakso, K. (University of Oulu, (Finland). Department of Biology) | Paoletti, E. | Huttunen, S.
Two holm oak (Quercus ilex L.) sites in Tuscany, Central Italy, were studied in July 2000. Leaf morphological characteristics (area, dry weight, specific dry weight, water content, epicuticular wax amount, stomatal density) and leaf fluorescence were measured. Ozone flux into the leaves was calculated on a stomatal conductance basis. Among the measured parameters, only stomatal density and wax amount significantly differed between the sites. This response might indicate an adaptation to air pollutants, of which tropospheric ozone might be of the greatest importance
Mostrar más [+] Menos [-]Long-term effects of pollutants on forest vegetation in Central Spis region
2002
Mankovska, B. (Forest Research Institute, Zvolen (Slovak Republic))
Pollution problems in forest ecosystems resulting from 100 year long operation of three smelter complexes in Central Spis are reviewed. Original data are presented with respect to temporal and spatial trends of nitrogen, sulphur and heavy metal pollution, and elemental composition of individual aerosols on leaf surface. Spruce stands in Central Spis are loaded by pollutants 1.7 times more than are critical values and the highest concentrations of As, Fe, Hg, and N were found in this region. Low Tatra National Park was the cleanest region where no element maxima were found
Mostrar más [+] Menos [-]Spatial distribution of ectomycorrhizas in Scots pine stand influenced by long-term pollution from copper industrial region in Poland
2002
Leski, T. | Rudawska, M. (Polish Academy of Sciences, Kornik (Poland). Institute of Dendrology)
A long-term effect of heavy metal pollution originating from Copper Smelter and Refinery Division Glogow on a Scots pine stand was carried out in the protective zone surrounding the smelting/refining plant. The effect of enhanced Cu, Pb and Zn availability on the structure of ectomycorrhizal communities was assessed above- and below-ground among several subplots dominated by Scots pine (Pinus sylvestris). Three different approaches were performed: sporocarp inventories, morphological analysis of ectomycorrhizal roots and molecular techniques based on PCR-RFLP method. Only a few sporocarps of ectomycorrhizal species were observed
Mostrar más [+] Menos [-]Needle traces of Scots pine as air pollution indicators
2002
Konopka, B. (Forest Research Institute, Zvolen (Slovak Republic))
Needle retention, needle density, height and radial increments were surveyed on Scots pine (Pinus sylvestris L.) in four forest regions, In the each forest region research was conducted on seven about 45-year-old pines. The Needle Trace Method (NTM) was used to determine needle retention and needle density along the main stem retrospectively for the last four decades. The NTM invented by Kurkela and Jalkanen is based on the examination of the vascular bundles connecting the needles and shoot pith. There are presented the long-term average values of needle retention in the particular forest regions, their differences. Needle retention and needle density reflected air pollution stress on the pines
Mostrar más [+] Menos [-]Sensitivity of adult beech and spruce trees of a mixed forest to chronic ozone exposure: findings from a free-air ozone fumigation experiment
2002
Nunn, A. J. (Technische Universitaet Munchen, Freising (Germany). Lehrstuhl fur Forstbotanik) | Reiter, I. M. | Heerdt, Ch. | Haberle, K. H. | Langerbartels, Ch. | Werner, H. | Sandermann, H. | Fabian, P. | Matyssek, R.
The study aims at assessing response patterns to chronic O3 exposure in adult forest trees, examining physiological and structural responses at the organ and whole-tree level for consistency by means of biochemical and ecophysiological analyses. Through comparison between the two O3 regimes, conclusions can be drawn about processes, which are at risk or already affected by ozone under the unchanged, prevailing stand conditions. Responses are related to the O3 influx into leaves as a measure of the physiologically effective O3 dose and cross-compared with the AOT 40 concept which is being validated on the two O3 fluxes and AOT40-related responses in biochemical, ecophysiological and structural tree parameters
Mostrar más [+] Menos [-]Progressive methods of increasing the survival of planting stock in the reforestation of localities affected by air pollutants
2002
Tucekova, A. | Sarvas, M. (Forest Research Institute, Zvolen (Slovak Republic))
Possibilities of the use of progressive methods in artificial regeneration of areas affected by air pollutants are namely modification of soil environment, active protection of planting stock against root desiccation, use of containerized planting stock for artificial regeneration of clearings, which resulted from air pollution
Mostrar más [+] Menos [-]