Limitations for in situ conservation are discussed in the light of variable environmental conditions and population characteristics. Environmental influences like clear cutting, over utilisation, immission load, climatic change, catastrophes and diseases can set limitations for in situ conservation. Genetic limitations can be set by narrow genetic base, badly adapted populations or hybridization with other species and/or cultural varieties.
Necessity for double conservation measures, reintroduction of rare species from reestablished adaptable populations and limitations for natural regeneration are discussed. The problem of species integrity versus hybridization and enlarged genetic base is mentioned.