Conservation of noble hardwoods in Europe

This paper is a summary of the work carried out within the European Forest Genetic Resources Programme network on gene conservation of noble hardwoods. The species classified as noble hardwoods are all of minor economic importance in European forestry owing to their low proportion in forests. For commonly occurring species the in situ multiple population breeding system (MPBS) is suggested. Some of the noble hardwoods occur together and whenever possible, their combined gene conservation is suggested. If possible, some of the subpopulations will be extended to 200-300 ha to match the objective of gene conservation of associated species. For rarely occurring species, grafting of trees and establishment of plantations of grafts in seed orchards or clonal archives are suggested to increase the effective population size. The progenies from such an orchard or archive are planted in forests. For Castanea sativa Mill., which is a multipurpose species, separate gene conservation of fruit cultivars and populations in nature is suggested. The severe threat from Dutch elm disease makes it necessary to establish hedges of Ulmus species to avoid infection of the disease via Scolytus insects. Whenever possible, MPBS in situ gene conservation of Ulmus glabra Huds. and Ulmus laevis Pall. should be carried out.