Abstract
Extensive tall-trunk orchards, an important element of the central European landscape since the Middle Ages, conserve potential for the future regarding their biodiversity, land use policy and agricultural value. For these reasons, extensive tall-trunk orchards are interesting with regard to nature conservation. Once the management of these low-productivity vegetation sites ceases, the habitat is threatened by successive overgrowth by shrub vegetation. Taking abandoned tall-trunk cherry orchards with dry/mesophilous grassland undergrowth in the locality of Kaňk as an example, the degree of colonization of orchards by woody species and differences in the structure of vegetation cover in different periods after abandonment were monitored. The results showed that the cover of cherry trees in orchards abandoned before 1990 was approximately 30% lower than in orchards abandoned after 2000. The cover of the herb layer in orchards abandoned before 1990 was approximately 60% lower than in orchards abandoned after 2000. The species diversity of orchards abandoned before 1990 was statistically significantly lower than that of orchards abandoned after 2000. The total cover of all species in habitat in areas of medieval ore extraction was approximately 50% lower than that in land originally used for farming.