Abstract
Autochthonous genetic resources of woody plants have become seriously endangered in Flanders because of the particularly low and fragmented forest cover, centuries of intensive forest use in this highly populated area and the wide-spread usage of non-autochthonous planting stock in reforestation and landscape plantings. Intraspecific hybridisation between remnant autochthonous populations and foreign genotypes, which can show inadequate adaptation, may influence the autochthonous genetic constitution and fitness in the long term. As several European countries face similar problems, the objective of this paper is to outline the conservation measures that are taken in Flanders. The central aim is to maintain and create the necessary conditions for natural and flexible evolution of the genetic diversity of autochthonous trees and shrubs. An inventory survey to locate remaining autochthonous populations was started in 1997 and will be completed in 2006. Relict populations are preserved in clonal banks. Central issues are the production of autochthonous planting stock through in situ seed collection, the approval of seed sources and stands and the creation of seed orchards. Conservation actions are discussed.