Article

The manifold and increasing human influences on the genetic structures of tree populations make it necessary to devise measures for conservation of forest genetic resources. After presenting a definition of gene conservation, the various objectives of forest tree conservation are considered. Because forest trees are long-lived plants and still at a relatively low level of domestication, the conservation of the genetic adaptability of their populations to environmental changes should be emphasized. This implies that the choice among candidate populations for conservation should be based on the results of surveys of genotypes at marker gene loci. In view of the expense involved, and the long-term importance of this step, the quality of gene markers and the information on their mode of inheritance becomes critical. Besides marker gene loci, the expression of genetically controlled adaptive phenotypic traits deserves proper weight. The selection criteria are then estimates of certain parameters, such as the adaptive potential, the genetic meaning of which must be made transparent. Methods of dynamic conservation should be given preference because of the environmental situation of tree populations. Conservation in situ requires high sylvicultural skills. The combination of these prodecures with conventional static conservation ex situ induces flexibility and is very promising. Problems exist as to how to sample populations and how to measure their variation. Current research needs are indicated.