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Criteria for the acceptance of seed stands as basic material in the Selected Category.

All stands proposed for inclusion in the National Register will be inspected by the Forestry Commission who will consider the following:

  • Origin: The clear designation of the stand as material of indigenous origin, of non-indigenous origin or of unknown origin must be determined.


  • Location and isolation: Stands need to be situated at a sufficient distance from poor stands of the same species or from stands of a related species or variety which can form hybrids with the species being considered. This requirement is particularly important when the candidate stand is of indigenous origin and surrounding stands are not indigenous. 


  • Effective size of population: Stands must consist of one or more groups of trees, well distributed and sufficiently numerous to ensure adequate interpollination. To avoid the unfavourable effects of inbreeding, there must be a sufficient number of individuals on a minimum area. Plantations of coniferous species less than 4 hectares in area will not usually be considered.


  • Age and development: Stands need to consist of trees which have reached an age at which acceptance criteria can be clearly judged.


  • Uniformity: The individuals which comprise the stand must show a normal degree of variation in morphological characters.


  • Adaptation: There must be evidence that the material is acceptably adapted to the region of provenance or seed zone altitude band for which registration is sought.


  • Health and resistance: Stands should in general be healthy and show, in the place where they are growing, maximum resistance to harmful organisms and to adverse external conditions (other than resistance to damage by air pollution).


  • Volume production: Where volume production is an essential criterion for approval it must be superior to the accepted mean under similar ecological conditions. 


  • Wood quality: This will be taken into account and may in certain circumstances be an essential criterion.


  • Form or growth habit: Proposed stands need to show particularly good morphological features especially straightness and circularity of stem, branching habit, small size of branching and natural pruning; a low proportion of forked trees and of those showing spiral grain is expected.


Last updated: 22nd November 2017