A SYSTEMATIC-APPROACH TO THE CONSERVATION OF GENETIC-RESOURCES OF TREES AND SHRUBS IN DENMARK

A Strategy for the Conservation of Genetic Resources of Trees and Shru bs in Denmark was prepared in 1991/93. The objective of the strategy i s to secure the ability of the species covered to adapt to environment al changes, and to maintain the basis for future improvement work. The strategy includes 75 tree and shrub species of actual or potential us e for planting in Denmark. Unless protective measures are taken, the s ize and constitution of the genetic variation of these species will, a s a result of present human influence, most likely be affected in the medium-to-long term in a way that may reduce their adaptability and ut ility significantly. The article focuses on the systematic approach to gene resource conservation taken in Denmark. This approach provides a n overview of the conservation effort required, estimated as a number of conservation stands with a minimum size and a specified geographica l distribution for each species. A review of human influence on the fo rest genetic resources since early forest development provides the rel evant background. Emphasis is given to prevailing silvicultural practi ces. The genetic resources in Denmark will, in general, be conserved i n evolutionary conservation stands, in situ or ex situ. For most speci es a network of conservation stands is required to cover the spectrum of assumed genecological variability. A preliminary genecological zona tion, the biology and the distribution of each species have served to estimate the required number and distribution of conservation stands. From 2 to 15 conservation stands are considered adequate for the diffe rent species. The estimated number of conservation stands to conserve the genetic variation of the 75 species is approximately 600. Around 5 00 will be in situ and around 100 ex situ. The total area required is approximately 1800 ha (excluding isolation zones) or 0.4% of the total forest area and 5% of the natural forest area in Denmark. The size of the area corresponds approximately to the area of certified seed stan ds/seed production areas in Denmark. The conservation of genetic resou rces is not pursued by imposing restrictions on the use of the genetic material. The philosophy of the strategy is to effect an insurance an d keep all options open. The wise use of the genetic resources will be encouraged by other means. Where target species can be identified and (gene) ecological zones defined, the approach described may be used e lsewhere to provide a quick and realistic overview of conservation nee ds and costs.