This report provides survey of the actual results of genetic investigations concerning the impact of nature orientated forest management on genetic variation of Silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.).
For Silver fir, the results indicate that genetic structures differ only little among collectives of various tree-classes (dominant, intermediate and suppressed trees). However, the lower tree-classes revealed a higher genetic multiplicity and significant higher values of heterozygosity when compared to dominant trees. Thus, no negative impact on the adaptive potential will be expected if intermediate and suppressed trees are transformed into uneven-aged or structured forest types. The comparison of an untreated and a thinned beech population revealed only little deviation in genetic structures. Thus, it can be assumed that selection caused by thinning does not appear to differ from natural selection.
The investigation on diameter orientated selective utilization in beech populations revealed that especially fast utilization periods might have negative effects on genetic variation. In order to preserve genetic variation, long utilization periods, regeneration periods as well as small structured utilization should be favoured.