Swiss Federal Institute for Forest, Snow and Landscape Research

About: Swiss Federal Institute for Forest, Snow and Landscape Research is a facility organization based out in Birmensdorf, Switzerland. It is known for research contribution in the topics: Climate change & Soil water. The organization has 1256 authors who have published 3222 publications receiving 161639 citations. The organization is also known as: WSL.

Different tree-ring responses of Norway spruce to air temperature across an altitudinal gradient in the Eastern Carpathians (Romania)

Abstract: A global increase in temperature could potentially increase the trees’ growth at high altitude and decrease at low altitude. Another immediate consequence would be an increase of the altitude threshold where the inversion of tree growth response to temperature occurs. The first network of 18 tree-ring chronologies of Norway spruce (Picea abies) from the Eastern Carpathians (Romania) was studied in relation to the climatic factors and regional patterns in tree growth responses to climate. The sites are distributed along a latitudinal and altitudinal transect. The tree growth reaction to climate variability was analyzed by means of response functions. We used redundancy analysis (RDA) to identify regional patterns in the climatic response. The Norway spruce diameter growth patterns in Eastern Carpathians from Romania correspond to different climatic responses according to three elevation levels: low (≤1000 m a.s.l.); intermediate (1000–1300 m a.s.l.); high (≥1300 m a.s.l.). At high altitudinal level tree growth is strongly limited by summer temperatures. This climatic signal progressively decreases with decreasing altitude and increasing mean temperature. Tree growth at low elevation sites is controlled mainly by summer precipitations and in the intermediate elevation sites there is not any statistically significant correlation with climatic variables. At elevations of 1000–1100 m a.s.l., at a mean temperature of 13–13.5 °C in June and 15.5–16 °C in July, further increases in mean temperature result in an inversion of the relationship between tree-ring growth and temperature (i.e., the response becomes negative). A global increase in temperature could potentially increase the trees’ growth at high altitude and decrease at low altitude. Another immediate consequence would be an increase of the altitude threshold where the inversion of tree growth response to temperature occurs.

Four-year growth dynamics of beech-spruce model ecosystems under CO2 enrichment on two different forest soils

Abstract: To elucidate how atmospheric CO2 enrichment, enhanced nutrient supply and soil quality interact to affect regrowth of temperate forests, young Fagus sylvatica and Picea abies trees were grown together in large model ecosystems. Identical communities were established on a nutrient-poor acidic and on a more fertile calcareous soil and tree growth, leaf area index, fine root density and soil respiration monitored over four complete growing seasons. Biomass responses to CO2 enrichment and enhanced N supply at the end of the experiment reflected compound interest effects of growth stimulation during the first two to three seasons rather than persistent stimulation over the whole duration of the experiment. Whereas biomass of Picea was enhanced in elevated CO2 on both soils, Fagus responded negatively to CO2 on acidic but positively on calcareous soil. Biomass of both species profited from enhanced N supply on the poor acidic soil only. Leaf area index on both soils was greater in high N supply as a consequence of a stimulation early in the experiment, but was unaffected by CO2 enrichment. Fine root density on acidic soil was increased in high N supply, but this did not stimulate soil respiration rate. In contrast, elevated CO2 stimulated both fine root density and soil CO2 efflux on calcareous soil, especially towards the end of the experiment. Our experiment suggests that future species dominance in beech-spruce forests is likely to change in response to CO2 enrichment, but this response is subject to complex interactions with environmental factors other than CO2, particularly soil type.

Atmospheric deposition on Swiss Long-term Forest Ecosystem Research (LWF) plots

Abstract: Atmospheric deposition of the major elements was estimated from throughfall and bulk deposition measurements on 13 plots of the Swiss Long-Term Forest Ecosystem Research (LWF) between 1995 and 2001. Independent estimates of the wet and dry deposition of nitrogen (N) and sulfur (S) on these same plots were gained from combined simplified models. The highest deposition fluxes were measured at Novaggio (Southern Switzerland), exposed to heavy air pollution originating from the Po Plain, with throughfall fluxes averaging 29 kg ha−1 a−1 for N and 15 kg ha−1 a−1 for S. Low deposition fluxes were measured on the plots above 1800 m, with throughfall fluxes lower than 4.5 kg ha−1 a−1 for N and lower than 3 kg ha−1 a−1 for S. The wet deposition of N and S derived from bulk deposition was close to the modeled wet deposition, but the dry deposition derived from throughfall was significantly lower than the modeled dry deposition for both compounds. However, both the throughfall method and the model yielded total deposition estimates of N which exceeded the critical loads calculated on the basis of long-term mass balance considerations. These estimates were within or above the range of empirical critical loads except above 1800 m.