Distinguishing between the indigenous and non-indigenous character of tree and shrub species is problematic because of trade, transfer and planting during the past centuries. Palaeobotanic research and research of written sources and toponimes have shown the indigenous character of approximately 100 woody plants (excluding brambles). The author has developed a method with a number of criteria, to measure the indigenous nature of specific trees or bushes. Original indigenous trees and shrubs are found especially in old forest areas, in old hedges, along meandering streams etc. They have survived through the centuries as polarded or coppiced trees, or by means of forest management in the past, in such a way that the fruits or grafts of the region are used. The large scale planting of plant material from other flora-regions results in a process of flora-falsification, and which is a serious threat for rare and extinguishing indigenous populations. The author argues for the use of indigenous plants in forest development as a contribution to conservation of nature and genetical biodiversity.