Wald und Klimawandel.Forum für Wissen 2006: 71 S.
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Wohlgemuth, T.; Bugmann, H.; Lischke, H.; Tinner, W.,
2006:
Wie rasch ändert sich die Waldvegetation als Folge von raschen Klimaänderungen?Wald und Klimawandel. Forum für Wissen 2006: 7-16.
AbstractHow rapidly does forest vegetation change due to rapid climatic change? Current predictions of future climates show a global increase of mean temperatures of 1.4 to 5.8 °C. How rapidly can forest vegetation adapt to such predicted large changes, and in which way? We looked for answers in three different disciplines: ecological modelling, palaeoecology and succession theory. We found that changes of forest vegetation after rapid climatic changes can be continuous or abrupt. Rapid or abrupt changes may result within years to decades, among others, from marked drought as a direct effect of climate warming, limiting tree growth in the driest parts of Switzerland within a few years or decades. Indirectly, climate warming affects forest vegetation by forest fires, windstorms and, consequently, insect outbreaks. Questions relevant to forestry arise from these considerations: What is the most suitable combination of tree species for which management should aim in the future, and how do we adequately manage protectiKeywordsabrupt climate change, ecological modelling, Holocene, Switzerland, vegetation switch |
Rebetez, M.,
2006:
Mehr Trockenheit bei wärmeren Temperaturen? Trends von Temperatur- und Niederschlagsverhältnissen in der Schweiz.Wald und Klimawandel. Forum für Wissen 2006: 17-21.
AbstractTemperature and precipitation trends in Switzerland. During the 20th century, worldwide temperatures have increased by 0.7°C. The 1990's was the warmest decade but temperatures should become even higher during the first decade of the 21st Century: 5 among the 6 warmest years were measured between 2001 and 2005. In Switzerland, temperature trends are stronger than on a global scale: an increase of 1.3 to 1.7°C was recorded during the 20th century on the northern side of the Alps, 1.0°C on the southern side respectively. Climate models expect increasing strong precipitation events, in Switzerland as well as worldwide along with an increasing variability of precipitation, in general. This means that stronger precipitation as well as more drought events must be expected in the future. In Switzerland, an increase in the frequency of drought episodes can already be noticed on the southern side of the Alps.Keywordsclimate, climate change, precipitation, Switzerland, temperature change |
Rigling, A.; Dobbertin, M.; Bürgi, M.; Feldmeier-Christe, E.; Gimmi, U.; Ginzler, C.; Graf, U.; Mayer, P.; Zweifel, R.; Wohlgemuth, T.,
2006:
Baumartenwechsel in den Walliser Waldföhrenwäldern.Wald und Klimawandel. Forum für Wissen 2006: 23-33.
AbstractTree-species change in the Scots pine forests of Valais The Valais is among the most extreme inner-Alpine dry regions. The distinct temperature increase of the recent years results in increasing drought stress for plants during dry years. In Valais forest vegetation is presently in change: mortality processes in Scots pine (Pinus sylvestris L.) go along with an increase of broadleaved trees, mostly downy oak (Quercus pubescens Willd.). A combined approach (assessment of forest structures on a regular grid, intensive monitoring and experimental plots, and analysis of past forest management) was applied to analyze the shift in tree-species composition and to keep apart the impact of changes in climate and land-use. The shift from pine to oak was most pronounced on dry sites, where pine mortality was highest and oak regeneration most frequently. Pine mortality was highest after dry years, whereas oak was less affected. Although oak regeneration seems to profit from the dryer climate, the changes of the land-useKeywordsbioindication, climate change, drought, land-use change, Pinus sylvestris, Quercus pubescens |
Dobbertin, M.; Giuggiola, A.,
2006:
Baumwachstum und erhöhte Temperaturen.Wald und Klimawandel. Forum für Wissen 2006: 35-45.
AbstractTree growth and elevated temperatures Between 1864 and 2000 spring and summer temperatures in Switzerland have increased by 0.8°C per 100 years. Climate models predict a more than doubling of this temperature rise by the middle of this century. Depending on the limiting factors for tree growth temperature increase may lead to different growth responses. Tree provenance trials along elevation gradients were used to study the effect of future climate warming. With increasing elevation tree stem and height growth declines and needles become shorter. High elevation and northern provenances are optimally adapted to a short growing season, but cannot completely utilize the longer growing season when planted at low elevation. They may respond less to climate warming than low elevation trees if planted at high elevation. Needle elongation pattern of European larch in the Engadin valley corresponds to an upward shift of 200 m over the past 20 years which is in agreement with the observed temperature increase in spriKeywordsstem growth, elevation gradient, growth period, shoot growth, needle elongation, drought |
Menzel, A.,
2006:
Zeitliche Verschiebungen von Austrieb, Blüte, Fruchtreife und Blattverfärbung im Zug der rezenten Klimaerwärmung.Wald und Klimawandel. Forum für Wissen 2006: 47-53.
AbstractChanges in leaf unfolding, flowering, fruit ripening and leaf colouring due to recent climate change The onset of seasons, as observed in the seasonal cycle in nature, has undergone major shifts during recent decades. Spring phenological phases, such as leaf unfolding and flowering, are continuously advancing. The onset of summer phases, such as flowering or fruit ripening, is also advancing. In contrast, the picture of autumn is more heterogeneous with partly later onset of leaf colouring and leaf fall. A new comprehensive European study (COST725) revealed that flowering and leaf unfolding in spring (75 218 records) have advanced by 2.5 days / decade over the last 30 years. In total the vegetation period in Central Europe is now up to two weeks longer than 30 years ago. This signal, which is most apparent in Germany and Switzerland in the mid 1980s, can be attributed to warming due to the anthropogenic greenhouse effect. This far-reaching study within the COST725 action further revealed that the advance ofKeywordsphenology, vegetation period, spring, autumn, climate change |
Walther, G.-R.,
2006:
Palmen im Wald? Exotische Arten nehmen in Schweizer Wäldern bei wärmeren Temperaturen zu.Wald und Klimawandel. Forum für Wissen 2006: 55-61.
AbstractPalms in the forest? Exotic species increase in Swiss forests with warmer temperatures. Global warming induced manifold impacts in various ecosystems of the world. Changes in the behaviour and distribution of indigenous plants and animals have increasingly been reported. However, not only native species respond to changing environmental conditions, the same applies to introduced species. A good example of a warming induced invasion is documented for forests along the shores of Lago Maggiore in southern Switzerland, where evergreen broad-leaved exotics successfully colonize former deciduous forests. The remarkable aspect of this process is that this trend is not restricted to a single invasive species but includes a whole suite of evergreens, which are about to establish a new community. Based on the invasion history of the introduced palm Trachycarpus fortunei, the mechanisms and limiting factors of this invasion process are presented and discussed in respect of present and future climatic conditions.Keywordsclimate change, biological invasions, bioindicator, vegetation shift, Ticino |
Zimmermann, N.; Bolliger, J.; Gehrig-Fasel, J.; Guisan, A.; Kienast, F.; Lischke, H.; Rickebusch, S.; Wohlgemuth, T.,
2006:
Wo wachsen die Bäume in 100 Jahren?Wald und Klimawandel. Forum für Wissen 2006: 63-71.
AbstractWhere do the trees grow in 100 years? The expected climatic change during the coming decades will result in a marked change of the distribution patterns of the tree species in Switzerland. In general most of the species will advance to higher elevations. Due to predicted decreases of summer precipitations, deciduous tree species with moderate to high water demands will eventually be handicapped. Trees will probably adapt more slowly than the rate of climate changes and may thus show lagged responses. On the one hand, trees move only by seed dispersal during generations, a slow process. On the other hand, continuous anthropogenic land use slows down the potential spread of trees into new habitats, at least at the alpine treeline. In order to minimise the risks of a strong climate change for forestry, we propose to manage current forests towards mixed and species-rich stands.Keywordsclimate change, vegetation distribution, vegetation models, species shift, tree line shift, land use change, lagged response, tree species migration |