Refine search
Results 61-70 of 184
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)
Show more [+] Less [-]Restoration of functioning forest ecosystems in the Krusne Hory Mts.
2002
Podrazsky, V. | Karas, J. (University of Agriculture, Prague (Czech Republic). Faculty of Forestry)
Research project main aims are coordinating, summarizing and making interpretation from the research results from the region of interest. Further targets are to focus, concentrate and promote research activities of relevant departments of the Faculty of Forestry in this area. Intention of organising institution is to create a material, grouping together research results available from the Ore Mts., forming a basis for results exchange and launching the data as well as for results utilisable in the forest practice in this region
Show more [+] Less [-]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
Show more [+] Less [-]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
Show more [+] Less [-]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
Show more [+] Less [-]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
Show more [+] Less [-]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
Show more [+] Less [-]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
Show more [+] Less [-]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
Show more [+] Less [-]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
Show more [+] Less [-]