86 FOREST REPORT 2005
4.6 Genetic resources
Genetic material passed down naturally from generation to generation is the best guarantee that trees will be able to adapt optimally to changing environmental conditions.
Maintaining and promoting genetic diversity is a core task of forest policy.
To protect genetic resources, there are special regulations for managing “forests of special genetic interest”.
Genetic diversity
Trees react differently to chang- es in environmental conditions.
Badly adapted trees pass on lit- tle or nogenetic material to the next generation, whereas well- adaptedindividuals of the same species producemore offspring.
Their genetic material ensures thelong-termsurvivalof the tree species. This natural selection processcanlead,in thecourse of time, to thedevelopment ofanew race that candealbetterwith the local environmental conditions.
Genetic diversity is the prequisite forallforms of evolution.
Maintaining and promoting genetic diversity is thus one of themainchallenges of forest pol- icy.InSwitzerlandit isamatter of principle to interfere aslittleas possiblewith the propagation of trees.For this reason fewer trees arebeingplanted than previous- ly and trees regenerate naturally on80% of the forested area.This percentage islikely to rise in fu- ture(>4.2Regeneration).Where planting is necessary, for exam- ple, to produce valuable timber on theCentralPlateau,foresters use seedlings ofSwiss originap- propriate for the site.
4.6.1
Stands for seed harvesting
Beech seeds are collectedin theSihlforest for artificial tree regeneration.
87 4BIOLOGICAL DIVERSITY
FURTHERINFORMATION Swiss Federal Research Institute WSL 8903 Birmensdorf
Research Dept. LANDSCAPE Section Ecological genetics (0) 44/ 739 24 39
Swiss Agency for the Environment, Forests and Landscape SAEFL 3003 Bern
Forest Agency
Section Forest conservation and biodiversity
Section Species and biotope conservation
(0) 31/ 324 77 78
4.6.2
Genetic resources in the forest
Existingforests of special genetic interest (SGI), seed stands and seed plantations.
Category No.ofobjects Total area No.ofspecies Forests of special genetic interest
(SGI forests,Gene reserves) 5 1157 ha 3
Selected seed stands 366 2507 ha 33
Guaranteed source seed stands 1264 873 ha 30
Seed plantations 18 - 9
Genetic diversity is the prequisite for all forms of evolution.
Maintaining and promoting genetic diversity is thus one of the main challenges of forest policy.
This reproductive materi- al originates from forestswhose trees have specialcharacteristics, i.e. from so-called seed stands.
Requirements are, for example, straight growthandfewbranch- es, which are indicators of high quality timber. Attention is also paid to the trees’ hardiness and growth performance. In the 1990s the Swiss government re- corded the seed stands in ana- tionalseedstandregister(NKS).
Thisdatabase provides informa- tion about the characteristics of the stands and their locations and helps foresters find ecolog- ically suitable seed material for planting.
Forests of special genetic interest
Forests of specialgeneticinterest are intended to protect local tree populations with special genet- ic characteristics.They areman- aged in a way that ensures the maintenance of selected species and theirgeneticmaterial.Up to now, the federalgovernment has designatedfiveareasSGI-forests for the tree species sessile oak, silver fir and Norway spruce. In comparisonwith otherEuropean countries this is rather few, but the number ofSGIforests should riseconsiderably in future.
Wherever possible, SGI for- ests should beable to regenerate naturally. If, however, foresters have to intervene, they use only seedmaterialfrom the sameSGI forest. Commercial near-natural use of SGI forests is allowed as long as it does not threaten the maintenance ofgeneticresources.
