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结果 11-20 的 180
Mechanised site preparation and restoration of degraded site
2002
Ulbrichova, I. | Podrazsky, V. (Czech University of Agriculture, Prague (Czech Republic). Faculty of Forestry)
It was performed the study of the humus forms, quantity and pedochemical characteristics, further the study of plantation growth, and the dynamics in the period of 1994-1999. Negative impacts of the bulldozing were documented, acidification in the period 1994-1999 and the ameliorative role of the birch stand as well
显示更多 [+] 显示较少 [-]Macro and microscopic effects of polluted seasprays on Pinus halepensis needles in El Saler Natural Park (Valencia, Eastern Spain)
2002
Calatayud, V. (Fundacion CEAM, Valencia (Spain)) | Della Rocca, G. | Paoletti, E. | Sanz, M. J.
Coastal forest decline due to seasprays has been reported from all continents, both on broadleaves and conifers. The main cause has been identified in the presence of surfactants. Sea winds transport these substances to the leaves, where they are absorbed via cuticula and stomata producing indirect and also direct damage. The scope of this work is the macroscopic and microscopic assessment of the long term effects of polluted seasprays on Aleppo pines in natural conditions from the Saler coastline (Eastern Spain) inwards. Surfactants may be involved in the damage to Aleppo pine in El Saler as more severe episodes of damage have been observed in the last decade
显示更多 [+] 显示较少 [-]Attempt of using peach plant antioxidant system elements changes as a test-factor of acid stress
2002
Klymenko, O.E. | Klymenko, M.I. (Nikita Botanical Gardens UAAS, Simferopol (Ukraine). Steppe Department)
It was established the strong changes in elements of antioxidation system by the influence of acid stress. The different reaction of varieties in these conditions was discovered. More early ripening varieties were more sensitive to acid stress. The relative indexes of plant antioxidation system conditions were calculated. The relative evaluation of the sensitivity of studied varieties to the acid stress was done by those indexes. We propose to use index of common recovering activity of tissue as a test index for the estimation of different peach varieties to acid stress
显示更多 [+] 显示较少 [-]Effects of elevated CO2 and O3 on stem wood chemistry in trembling aspen, paper birch and sugar maple
2002
Anttonen, S. (Finnish Forest Research Institute, Suonenjoki (Finland). Suonenjoki Research Station) | Kostianen, K. | Vapaavuori, E. | Isebrands, J. G. | McDonald, E. | Sober, J. | Karnosky, D. F.
Global environmental change, including increasing atmospheric CO2 and tropospheric O3 is likely to impact forest growth and wood properties. Increase in CO2 enhances photosynthesis, growth and productivity. On the contrary, O3 is detrimental to forest vitality and yield. At present reports of long-term studies on the effects of combined exposures of CO2 and O3 on stem wood chemistry of deciduous trees are lacking. The aim of this study was to investigate the effects of CO2 and O3, singly or in combination, on stem wood chemistry of four-year old saplings of trembling asspen (Populus tremuloides) clones differing in ozone tolerance, paper birch (Betula papyrifera) and sugar maple (Acer saccharum)
显示更多 [+] 显示较少 [-]Is abundance of moth Bucculatrix ulmella affected by immissions?
2002
Kulfan, J. | Zach, P. | Suslik, V. | Zelinkova, D. (Slovak Academy of Sciences, Zvolen (Slovak Republic). Institute of Forest Ecology) | Anderson, J. (7709 N. Wall, Spokane, Washington (USA))
We studied whether the increased abundance of B. ulmella in 1997 was associated with environmental pollution from an aluminium plant. To clarify this question we selected nine study sites at a distance of 1.4-18 km (control) from the aluminium plant in Central Slovakia. We found a sigifnicant difference in the moth numbers between the third and fourth site even though these sites are distant from each other only about 200 m. Each site was exposed to pollution from different part of the plant complex producing specific emissions of different quantity. This might explain differences in the moth abundance within the polluted area
显示更多 [+] 显示较少 [-]Surface liming of immission clear-cuts: benefits and risks
2002
Podrazsky, V. | Ulbrichova, I. (Czech University of Agriculture, Prague (Czech Republic). Faculty of Forestry)
Presented study documents the effects of experimental liming on the forest soils and forest plantations (Norway spruce). Liming was performed in the top part of the Orlicke hory Mts., in the altitude 1100 m. Results documented mutual effects on the forest soil as well as on the newly established Norway spruce plantations. It was evaluated the effect of liming on the soil pH, soil adsorption complex, exchangeable nutrients. Special attention was paid to the nitrogen dynamics and to the plantation growth and nutrition
显示更多 [+] 显示较少 [-]Soil nutrients in a mature natural mixed forest exposed to elevated CO2
2002
Bucher-Wallin, I. K. | Schleppi, P. | Hagedorn, F. | Bucher, J. B. (Swiss Federal Research Institute WSL, Birmensdorf (Switzerland))
Elevated CO2 was shown to influence the nutritional status of exposed ecosystems. In an earlier experiment in model ecosystems in open-top chambers with young spruce and beech, the nitrate concentration of the soil solution was dramatically reduced after 4 years exposure to elevated CO2. This phenomenon was mainly interpreted as an immobilization of nitrogen in the soil. To test if such effects occur also in mature, undisturbed natural forests, we used facilities of the Swiss Canopy Crane project. Here in a mixed 120 years old forest the crowns of 30-35 m high broadleaved trees are fumigated with CO2 during the growing season since spring 2001. According to the results the soil is probably not yet much influenced by the fumigation of the tree crowns, and it is too early to estimate whether the observed nutrient effects are due to the CO2 treatment or to the natural variability of the soil
显示更多 [+] 显示较少 [-]The rate of PAHs accumulation in the pine needles (Pinus sylvestris L.) from selected regions with different types of PAHs emission
2002
Malawska, M. (Warsaw University, Warsaw (Poland). Faculty of Biology) | Staszewski, T. | Wilkomirski, B.
The investigation was carried out in three areas characterised by different levels and types of PAHs emission. The difference in total amount of PAHs in pine needles from investigated areas was accompanied by a significant changes in mutual ratio of PAHs with different number of rings
显示更多 [+] 显示较少 [-]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
显示更多 [+] 显示较少 [-]Acclimatory responses in Scots pine needles during three years of growth at elevated CO2 and temperature
2002
Luomala, E.M. (Finnish Forest Research Institute, Suonenjoki (Finland). Suonenjoki Research Station) | Lattinen, K. | Kellomaki, S. | Vapaavuori, E.
We studied the effects of elevated CO2 and elevated temperature on photosynthesis and composition of Scots pine needles during three years of treatments, started in August 1996. CO2 and temperature were elevated day- and year- round in closed-top chambers, which were constructed around naturally regenerated Scots pine trees growing at a nitrogen poor site. Our aim was to study, whether there is photosynthetic acclimation during three years of growth at elevated CO2 and elevated temperature in Scots pine, and whether acclimation response is connected to the aging of the needles
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