Beech forest communities in Bulgaria
|Original title:||Beech forest communities in Bulgaria|
|Authors:||Rossen Tzonev, Marius Dimitrov, Milan Chytrý, Veska Roussakova, Dobromira Dimova, Chavdar Gussev, Dimitar Pavlov, Vladimir Vulchev, Antonina Vitkova, Georgi Gogoushev, Ivajlo Nikolov, Daniela Borisova, Anna Ganeva|
Beech forests occupy considerable areas in the Bulgarian mountains. They are represented by communities of Fagus sylvatica (incl. F. moesiaca) and F. orientalis, and also by mixed stands of beech with Abies alba, Carpinus betulus, Quercus cerris, Q. dalechampii and Q. polycarpa. 494 releves sampled across the country were analysed by numerical methods. They were classified into 12 groups of Fagus sylvatica forests and 3 groups of Fagus orientalis forests. The analysis of Bulgarian Fagus sylvatica communities did not show a distinct pattern of geographic differentiation and did not support the concept of the alliance Fagion moesiacum, as accepted by many earlier authors. The differentiation patterns in the Bulgarian Fagus sylvatica forests mainly follow the gradients in soils and climate, and are similar to those in the Central European beech forests. Therefore we accept a syntaxonomical scheme, which emphasizes variation due to edaphic and local topoclimatic factors rather than due to large-scale geographical differentiation. This scheme is very close to that proposed by Willner (2002) for the southern Central European beech forests, and includes the alliances Luzulo-Fagion (acidophilous beech forests), Asperulo-Fagion (nutrient-rich beech forests), and Cephalanthero-Fagion (thermophilous beech forests). The communities of Fagus orientalis are markedly different from the communities of Fagus sylvatica, have a distinct floristic composition, and belong to the Euxinian alliance Fagion orientalis.