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.

Forest storm damage is more frequent on acidic soils

Abstract: Les forets au sol acide sont plus souvent endommagees par les tempetes. Nous avons etudie l'effet des proprietes chimiques des sols et des depots acidifiants (soufre et azote) sur les dommages dus aux tempetes durant les passages de « Lothar » et de « Martin » en decembre 1999. Les donnees de 969 sites en France, au sud de l'Allemagne et en Suisse ont ete analysees a l'aide de modeles de regression logistique multiple. Les variables liees de maniere significative aux dommages dus aux tempetes etaient les suivantes: le pays, le pH du sol, la proportion de coniferes, la declivite du terrain, le type d'humus, la hauteur des arbres et l'altitude. Dans la plupart des sites, les dommages n'etaient que partiels. La vitesse du vent n'etait pas liee de maniere significative aux dommages dans le modele global, mais dans un modele utilisant uniquement les donnees de France. Le pH du sol, qui s'avere etre l'un des principaux facteurs, etait plus bas dans les forets endommagees. Les taux de depots atmospheriques etaient etroitement lies a l'acidite des sols, mais pas directement aux dommages dus a la tempete. Meme si les mecanismes provoquant l'interdependance de l'acidite du sol et des dommages dus aux tempetes ne sont pas clairement elucides, l'acidite du sol devrait etre consideree comme un facteur risque de grande importance. En outre, cette etude realisee a large echelle confirme qu'une plus grande proportion d'arbres a feuilles caduques reduirait la sensibilite des forets aux dommages dus aux tempetes.

Methodical study of nitrous oxide eddy covariance measurements using quantum cascade laser spectrometery over a Swiss forest

Abstract: . Nitrous oxide fluxes were measured at the Lageren CarboEurope IP flux site over the multi-species mixed forest dominated by European beech and Norway spruce. Measurements were carried out during a four-week period in October–November 2005 during leaf senescence. Fluxes were measured with a standard ultrasonic anemometer in combination with a quantum cascade laser absorption spectrometer that measured N2O, CO2, and H2O mixing ratios simultaneously at 5 Hz time resolution. To distinguish insignificant fluxes from significant ones it is proposed to use a new approach based on the significance of the correlation coefficient between vertical wind speed and mixing ratio fluctuations. This procedure eliminated roughly 56% of our half-hourly fluxes. Based on the remaining, quality checked N2O fluxes we quantified the mean efflux at 0.8±0.4 μmol m−2 h−1 (mean ± standard error). Most of the contribution to the N2O flux occurred during a 6.5-h period starting 4.5 h before each precipitation event. No relation with precipitation amount could be found. Visibility data representing fog density and duration at the site indicate that wetting of the canopy may have as strong an effect on N2O effluxes as does below-ground microbial activity. It is speculated that above-ground N2O production from the senescing leaves at high moisture (fog, drizzle, onset of precipitation event) may be responsible for part of the measured flux.

Temperature-dependent genotype-by-genotype interaction between a pathogenic fungus and its hyperparasitic virus.

Abstract: The outcome of host‐parasite interactions may depend not only on the genotypes of the species involved but also on environmental factors. We used the fungus Cryphonectria parasitica, the causal agent of chestnut blight, and its hyperparasitic virus, Cryphonectria hypovirus‐1 (CHV1), to test for genotype‐by‐genotype‐by‐environment interactions in a host‐parasite system. In C. parasitica, infection with CHV1 induces a hypovirulent phenotype with reduced virulence toward the chestnut tree (Castanea spp.) and thus controls chestnut blight in many European regions. In contrast, uninfected virulent C. parasitica have nearly eradicated the American chestnut in North America. We applied a full factorial design and assessed the fungal growth and sporulation of four C. parasitica strains, uninfected and infected with each of the four known CHV1 subtypes, at 12°, 18°, 24°, and 30°C. We found a significant ( \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm...