Quantifier la valeur �cologique des milieux pour int�grer la conservation de la nature dans l'am�nagement des for�ts : une d�marche multicrit�res

Abstract

The integration of nature conservation in forest management plans still uses highly variable concepts and processes, mixing considerations related to naturalness and patrimonial or esthetical value. We propose a method based on the difference between conservation value (CV) and natural value (NV), and on the distinction between local and landscape scales. Criteria and indicators for CV and NV are computed on the basis of floristic observations and data usually collected by foresters and naturalists. The method is tested in south Belgium on 7 forests, 66 parcels and a little unexploited forest. Though CV and NV are correlated, the CV/NV ratio shows strong differences between habitat types, confirming the usefulness of the initial distinction. In the test sample, the unexploited forest, an oligotrophic alder wood and some mature oak and pine woods have the highest CV, whereas highest NV is obtained in the unexploited and the uneven-aged beech forests. The method can be used for the definition of priority conservation areas (Natura 2000), the design of strict forest reserves networks and the estimation of the ecological effect of habitat transformation scenarios.