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Potential Temporal and Spatial Responses of Forest Communities to Climate Change: Application of Two Simulation Models for Ecological Risk Assessment
1993
Kienast, F. | Brzeziecki, B. (Swiss Federal Institute for Forests, Snow and Landscape Research, Birmensdorf (Switzerland))
Two modeling approaches were applied to evaluate the potential risks of increasing atmospheric carbon dioxide concentrations and possible climate change on the vegetation cover of the Alpine region. The first model is a stochastic forest succession simulator, the second is a static regression type model. The questions of the study were as follows: (1) Which temporal vegetation changes might occur under given carbon dioxide and climate scenarios? (2) Which region of the Alps might be most susceptible to a vegetation change?
Show more [+] Less [-]Direct and Indirect effects and the Long-term Risks of Air Pollution on Forest Ecosystems:
1993
Skelly, J.M. (Pennsylvania State University, University Park (USA))
Tropospheric ozone is the most important single air pollutant of importance to forests in eastern United States. Both broadleaf and needled trees may suffer premature foliar senescence following even low ozone exposure years. Genetic sensitivity within species is likewise prevalent.
Show more [+] Less [-]Direct and Indirect Effects and the Long-term Risks of Climate Change on Forests: Carbon Balances in United Kingdom Forests
1993
Jarvis, P.G. (University of Edinburgh, Scotland (United Kingdom). Institute of Ecology and Resource Management)
The area of productive woodland in the UK has been increasing steadily since 1950, generally at about 20-30 thousand hectares per year. The current forest estate covers 2,1 million hectares, the annual growth in the total stored carbon in wood is 2,0 million tonnes. The annual UK output of carbon dioxide from the burning of fossil fuels is 162 million tonnes.
Show more [+] Less [-]Indirect effects and the Long-term Risks of Air Pollution on Eastern North American Temperate Forest Ecosystems: Insect Outbreaks
1993
Chappelka, A.H. (Auburn University, Alabama (USA). School of Forestry)
Air pollutants cause subtle changes in natural resistance that can prediscope plants to insect attack. The majority of reports in the area of plant-pollutant-insect interactions have been correlative in nature. In the last ten years, there has emerged a growing body of literature, the vast majority with herbaceous crops, reporting on cause-effect relationships among insects and their hosts.
Show more [+] Less [-]Direct Effects of Air Pollution on Forest Ecosystems of Western North America
1993
Peterson, D.L. (University of Washington, Seattle (USA))
Visible chlorotic injury and reduced foliar biomass are found in Pinus ponderosa and P. jefreyi in the mountains of southern California and the west slope of Sierra Nevada. Reduced tree growth and accelerated rates of forest succession has been documented in this area, with ozone resistant, shade tolerant species replacing P. ponderosa. There may also be some interactions among ozone, drought stress, insects and fungal pathogens.
Show more [+] Less [-]Indirect effects and the Long-term Risks of Air Pollution on Forest Ecosystems: Effects on Forest Soils
1993
Billett, M.F. (University of Aberdeen Scotland (United Kingdom))
Long-term changes in forest soils are characterised by decreases in soil pH, exchangeable base cations, percent base saturation and accumulation of heavy metals. Acidic deposition effects on forest soils can be demonstrated experientially either in the laboratory or in the field by stimulated acid treatments.
Show more [+] Less [-]Direct Effects on Boreal Forest Trees in Northern Europe
1993
Koski, V. (Finnish Forest Research Institute, Vantaa (Finland). Department of Forest Ecology)
Northern species not only tolerate but even benefit vegetatively from a slightly warmer climate than they have been adapted to. If the climatic warming remains below 5 celsius in annual mean temperature, the present forest will not be subject to direct disaster. Reproductive processes are likely to be enhanced through increased flowering and better seed maturation. There are few empirical studies on reproductive biology in new environments.
Show more [+] Less [-]Indirect effects and the Long-term Risks of Air Pollution on Eastern North American Forest Ecosystems: Pathological Problems
1993
Chappelka, A.H. (Auburn University, Alabama (USA). School of Forestry)
Air pollutants such as ozone may affect tree host-pathogen interactions by altering plant tissue susceptibility, plant resistance, pathogen virulence and inoculum density. Ozone has been shown to weaken trees in natural stands and increase their susceptibility to invasion by plant pathogens, such as Heterobasidion annosum. Ozone has also been shown to enhance disease development by fungi that are normally saprophytic in nature.
Show more [+] Less [-]Direct and Indirect Effects and the Long-term Risks of Air Pollution on Forest Ecosystems: A Call for Caution in Proper Diagnosis of Causes
1993
Skelly, J.M. (The Pennsylvania State University, (USA). Department of Plant Pathology)
Forest Scientists must recognize that numerous diseases and insect occurrences as well as more subtle environmental stresses are prevalent as causes of changes in forest health. Their interactions often lead to "natural" declines of individual tree species or site-species declines of multiple species. The role of air pollution should be carefully investigated in an integrative sense with these other endemic and sometimes epidemic outbreaks of biotic agents and environmental stresses.
Show more [+] Less [-]Direct and Indirect effects and the Long-term Risks of Air Pollution on Forest Ecosystems: Air Pollutants and Tree Ecophysiology
1993
Matyssek, R. (Swiss Federal Institute for Forest, Snow and Landscape Research, Birmensdorf (Switzerland))
The potential effects of long-term exposures to widespread low but raised concentrations above natural levels in Central Europe are still being discussed. This uncertainty results from an inadequate mechanistic understanding of the influence of air pollutants and other environmental factors of trees.
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