NEW INSIGHTS CONCERNING IDENTIFICATION, MANAGEMENT AND CONSERVATION OF INDIGENOUS TREES AND SHRUBS IN THE NETHERLANDS

In densely populated European countries like the Netherlands, old landscape elements such as ancient woodlands and ancient hedges are today rare. Owing to the introduction of exotic species and indigenous trees and shrubs imported from other climate zones, recognition of truly wild, i.e. autochthonous, individuals and populations is now problematical, posing challenges for forest management agencies, particularly at Natura 2000 sites. The author has developed a method for recognising genetically pure wild woody species, based on characteristics of the plant itself and those of the growing site. With this method, explained here, around 70% of the Netherlands has been surveyed, along with much of Flanders and part of the lower Rhine region of Germany. The results are illustrated with reference to two Dutch ancient woodlands, where new insights were obtained in terms of native status of the woody species and the ‘authenticity’ of the tree and shrub layer.