Woodland key habitats in northern Europe: concepts, inventory and protection

Abstract The woodland key habitat (WKH) concept has become an essential instrument in biodiversity-orientated forest management in northern Europe. The philosophy behind the concept is basically the same in all of the countries: to conserve the biodiversity of production landscapes by preserving small habitat patches that are supposed to be particularly valuable. This article reviews the definitions, inventories and implementation processes of WKHs in Sweden, Finland, Norway, Latvia, Estonia and Lithuania. Sweden and the Baltic countries have similar WKH models, while the models in Finland and Norway are clearly deviating. Depending on the country, the definitions emphasize different factors, such as soil and bedrock properties, stand structure and occurrence of indicator species. The mean size of the WKHs varies considerably, from 0.7 ha (Finland) to 4.6 ha (Sweden). The degree of formal protection also differs. Preservation of WKHs is primarily based on forest legislation in Finland, Estonia and Latvia, and on forest certification in the other countries. The implementation of the WKH concept is inconsistent between the countries, resulting in different sets of habitats being included in the WKH networks. This makes direct comparisons between the countries difficult, and may hamper the generalization of research results into other areas.