The question of non-indigenous forest species
- Basic principles
- Basic conditions
- Conditions for introduction
- The vegetation pattern which evolved in European forests during the postglacial migration of forest species, forming the existing forest regions, is regarded as a precious natural asset, which must be maintained. It should be respected as the most important basis of all silvicultural measures.
- Non-indigenous species (exotics) can, under some circumstances, supplement the indigenous vegetation pattern and increase the economic yield of forestry.
- All forest species which did not previously form part of a given natural plant association and which have been introduced from distant locations must be considered as exotic species.
- The introduction of exotic species should only be allowed after critical qualitative and quantitative tests.