ESTIMATION DE LA VALEUR ?COLOGIQUE DE LA V?G?TATION FORESTI?RE ET DES HAIES. APPLICATION AUX ?TUDES D'INCIDENCES

Estimation of ecological value of the vegetation of forests and hedges. Application to environment impact studies. ? Environmental impact assessments on most of the important building and development projects have been set up due to the law. Therefore, one needs to install methods to quantify effects of the project on the environment. On a first stage, it is interesting to know the quality of the present stade of woods and hedges. The example mentioned here concerns the effects of T.G.V. plans between the French border and the town of Ath. A method of assessment of ecological value of woods and hedges has been worked out. First of all, maps and aerial photographies have been used to identify and locate each vegetation unit. After that, a ground survey allows to give a score on the structure, the development of each layer, the species diversity, the species integration and artificiality. A global score is attributed to each community. By comparing them, it is possible to delimit the areas which should be first protected.