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This research focus studies how plants are related and how they respond to primary site factors in forests. Specifically, we are interested in the main growing factors such as light, temperature, soil moisture and nutrient availability and their effects on forest vegetation, including tree-growth. Tree growth is analysed as a function of the main growing factors mentioned above, by applying and further developing dendroecological methods. Our research provides new data based knowledge for the scientific community, for the forest management and for educational purposes.
Our research involves a large database containing both vegetation records and soil profile data from currently 1050 sampling plots (Fig. 2). For a sub-dataset, long-term data series are available of various environmental parameters, e.g. soil moisture (tensiometer measurements).
Dendroecological investigations are carried out at several case study sites, preferably where long-term data series of soil moisture and nutrient availability are readily available.
A large parameter set of morphological, chemical and physical soil data has been obtained from the soil profile analyses. Vegetation records are separated in the herb, shrub and tree layer. Additional site data such as climate and geology complete the data set at each plot.
All data are stored in an Oracle database; soil samples are archived in the “Pedothek” at WSL (Fig. 3). Successively, the database is extended with additional site parameters and new sampling plots.
Soil, vegetation and tree-ring data are analysed using approved methods:
The methods used for the analysis and interpretation of soil data are published in “Waldböden der Schweiz” (Volume 1). Soil morphology is recorded according to WSL standard field methods. Chemical and physical soil parameters are analysed in the laboratories at WSL.
Forest vegetation is recorded according to Braun-Blanquet (1964).
Standard dendroecological techniques are used to sample tree cores in the field and measure ring-width in the WSL tree-ring laboratory (Cook and Kairiukstis, 1990; Stokes and Smiley, 1968). A wide range of statistical methods is applied to analyse tree-growth as a function of environmental factors.
The following projects in the Research Unit Soil-Sciences are linked to the Research Focus Site Ecology:
Blaser P., Graf Pannatier E., Walthert L. 2007: The base saturation in acidified Swiss forest soils on calcareous and non-calcareous parent material. A pH-base saturation anomaly (in press).
Richter A., Walthert L., Frossard E., Brunner I. 2007: Does low soil base saturation affect fine root properties of European beech ( Fagus sylvatica L.)? Plant and Soil, 298: 69-79.
Weber P., Rigling A., Bugmann H. 2007: Radial growth responses to drought of Pinus sylvestris and Quercus pubescens in an inner-Alpine dry valley. Journal of Vegetation Science, 18: 777-792.
Ecological indicator values for Swiss forest plants (Webapplication)
Waldböden der Schweiz (3 volumes, covering soils all across Swiss forests)
Lorenz Walthert (Coordination, Database, Vegetation)
Stefan Zimmermann (Database)
Peter Lüscher (Site selection, Contacts)
Pascale Weber (Dendroecology)
Elisabeth Graf-Pannatier (Water balance models)
Marco Walser (Database, Fieldwork, Pedothek)
Roger Köchli (Fieldwork, Pedothek, Laboratory)
Alois Zürcher (Laboratory)
Daniel Christen (Laboratory)
Peter Jakob (Design Database)
Flurin Sutter (Design Database)
Zentrallabor WSL (Chemical analysis)
Zivildienstleistende und Praktikanten (Fieldwork, Laboratory, Database)