Seed orchards

Aspects of genetic diversity in Scots pine are reviewed with particular emphasis upon the interactions with silvicultural practices such as the use of natural or artificial regeneration. There is little evidence that greater use of artificial regeneration will result in decreased genetic diversity at the stand level. This result appears to hold whether the planted seedlings are derived from wild stands, from seed stands or from seed orchards. However, in the last instance, the orchard should contain at least 40 clones to provide the heterozygosity expected of natu-ral populations. There is limited knowledge of genetic diversity in adaptive traits such as cold hardiness or drought tolerance. Despite nearly a century of research into the genetics of Scots pine, there is still inadequate knowledge of the desirable level of genetic diversity in forests of this species and the interactions with manage-ment practices. However, current European regulations on Forest Reproductive Materials pay due attention to is-sues such as genetic conservation and matching of seed sources to regions. Therefore, it seems unlikely that cur-rent silvicultural practices will limit genetic diversity in Scots pine