Swiss Federal Institute for Forest, Snow and Landscape Research WSL

Soil protection

Soil compaction, climate change and pollutants: Such processes hamper the manifold functions of soils. We are searching for indicators that reflect the state of soils and are looking for ways how to protect forest soils.

In the Swiss legislation on environment protection, soil protection is defined as the maintenance of soil fertility. Referred to the forest this means that the self-preservation of a site-specific forest-biocoenosis with a natural regeneration should be sustainably guaranteed.

Soil – a talent in many ways

Kartierung der Spurtypen (unterschiedlicher Verformungsgrad) und des Verdichtungsrisikos als Grundlage für die Einsatzplanung der Forstmaschinen. Graphik: Peter Lüscher, Stéphane Sciacca
Mapping of various types of tracks (different soil deformation) and of the risk of compaction as a basis for the operational strategy of the forest vehicles. Graph: Peter Lüscher, Stéphane Sciacca/WSL
Tracks of a heavy forestry vehicle on a skidder trail after repeated vehicle crossings. Image: Marco Walser/WSL

Soils fulfil various functions. They are habitats of plants, animals, microorganisms and fungi and are consequently an important basic resource for human beings. Soils govern the percolation of water and dissolved substances by acting as a reservoir, a buffer and/or a filter and therefore, they are an important regulator in element cycling.

Soil functions are endangered by land cultivation practices and the emissions of harmful substances from various sources. The main threats which endanger soil fertility in forests and which we investigate are soil compaction by heavy forest harvesters, soil contamination with harmful substances, climate change and its impact on soil organic matter as well as alterations of soil due to land-use change.

Under the research topic “Soil protection”, we investigate the main threats and their effects on the soil functions and hence on soil fertility.

Current and future research activities include field and laboratory investigations on:

  • the impacts of forest-harvesters on soil properties and functions and its regeneration,
  • the mapping of risk assessment with regard to erosion and landslides,  
  • the assessment of ecological risks (e.g., floodwaters),
  • the interrelation of soil pore space and distribution of tree roots,
  • the interrelationship between land-use change (e.g., afforestation, litter removal, application of wood ash) and soil chemical properties,
  • the investigation of the gas exchange between the soil and the atmosphere depending on the degree of compaction.
     

In addition, extention and maintenance of the data base of soil chemical and physical properties serve as an important tool in order to deduce indicators of soil health, pedotransfer functions and ecological standards for the validation of forest soils.

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