08G1

G. Forests

Acidophilic common beech (Fagus sylvatica) forests

Relationships with habitat classifications. EUNIS: G1.6921 Southeastern Moesian woodrush-beech forests, G1.6931 Balkan Range acidophilic beech forests; PAL. CLASS.: 41.1921 Southeastern Moesian woodrush-beech forests, 41.1931 Balkan Range acidophilic beech forests; HD 92/43: 9110 Luzulo-Fagetum beech forests.

Conservation status. BDA, BC, HD.

Category. Vulnerable [VU – A1, 2 B1 C1 D2 E2 F2 G1 H2 J L3].

General characteristics. The habitat comprises acidophilic deciduous and mixed, deciduous-coniferous forests with Fagus sylvatica as the main ediphicator. They develop on relatively poor (sometimes eroded) soils (Dystric Cambisols) and rankers (Umbric Leptosols). The bedrock is mostly diorite, granite, riolite, sandstone, crystalline schist, etc. They occupy mostly steep slopes with different exposure, in both shadow and sun. The altitude varies considerably from 700 up to 1700 m. At lower altitudes (700 – 1100 m alt.) occur monodominant beech forests and mixed broad-leaved forest with relatively high abundance of the Hornbeam (Carpinus betulus) and the Sessile oak (Quercus dalechampii), and in some places also with Birch (Betula pendula). At higher altitudes (1300–1700 m alt.) the Common beech makes both monodominant and mixed forests with the fir (Abies alba) and the spruce (Picea abies). Solitary trees of Sorbus aucuparia, Populus tremula, Betula pendula and Pinus sylvestris also occur. The acidophilic beech forests have well developed herbaceous cynusium dominated by species whose distribution is associated with acidic soils: Calamagrostis arundinacea, Deschampsia flexuosa, Luzula luzuloides, L. sylvatica, Milium effusum, Oxalis acetosella, Poa nemoralis, Pteridium aquilinum, Vaccinium myrtillus. In some communities a great number of mosses also participate:Brachytheciastrum velutinum, Homalothecium lutescens, Isothecium alopecuroides, Leucobrium glaucum, Plagiomnium affine, Pleurozium schreberi,Polytrichastrum formosum, etc.

Syntaxonomically the acidophilic beech forests belong to class Querco-Fagetea, order Fagetalia sylvaticae, alliance Luzulo-Fagion.

Based on soil characteristics (mechanical structure, presence of stones, strength, richness, humidity) and floristic composition, the following subtypes of acidophilic beech forests can be defined:

1. Typical acidophilic beech forests (association Luzulo luzuloidis-Fagetum sylvaticae). A large group of acidophilic beech forests in Bulgaria belong to this subtype. They occur in Balkan Range, Sredna Gora Mts., Ossogovo Mts., Rhodopi Mts., Vassilyovska Mts. and Belasitsa Mts. They mostly develop between 1200 and 1500 m alt., and occupy steep slopes of different exposures. The soils are relatively shallow and poor Dystric Cambisols, Umbric Leptosols, and more rarely Eutric Cambisols. Constant and dominant species are Luzula luzuloides and Deschampsia flexuosa. Other frequent species are Calamagrostis arundinacea,Hieracium murorum gr., Mycelis muralis,and Poa nemoralis. In some phytocoenoses dominants and co-dominants are Bruckenthalia spiculifolia, Calamagrostis arundinacea, Juniperus communis, Vaccinium myrtillus, V. vitis-idaea, Veronica officinalis, and some mosses: Leucobrium glaucum, Pleurozium schreberi, Polytrichum juniperinum, etc.

The typical acidophilic beech forests belong to the association Luzulo luzuloidis-Fagetum sylvaticae. Two subassociations, Galietosum rotundifolii and Vaccinietosum myrtilli have been reported from the West Balkan Range. The plant diversity of the subassociation Galietosum rotundifolii is relatively bigger and with higher number of mesophytes and skiophytes: Cruciata glabra, Galium pseudaristatum,G. rotundifolum,Physospermum cornubiense, Pleurozium schreberi. The subassociation Vaccinietosim myrtilli is poorer in species and include Vaccinium myrtillus, V. vitis-idaea and Bruckenthalia spiculifolia.

2. Acidophilic beech forests on screes and stony terrains (group Geranium macrorrhizum-Fagus sylvatica). This subtype comprises beech forests which occupy places with exposed rocks, large stones and screes. They occur mostly between 1100 and 1500 m alt., on slopes with different, but mainly eastern exposure in Ossogovo Mts., Vassilyovska Mts., East Rhodopi Mts., Sredna Gora Mts., Balkan Range, North Pirin Mts., Belasitsa Mts,. Ruy Mts., and Rila Mts. The herbaceous synusium develops mostly among the stones, on Dystric cambisol. The prevailing species are Geranium macrorrhizum, Luzula sylvatica and Rubus hirtus. A well-developed moss synusium, dominated by Brachytheciastrum velutinum, Homalothecium lutescens, Isothecium alopecuroides, Plagiomnium affine, Polytrichum juniperinum, etc. occur on the screes there. The acidophilic beech forests on screes and stony places belong to the community Geranium macrorrhizum-Fagus sylvatica. The high frequency of some of the species typical for the neutrophilic beech forests such as Galium odoratum, Geranium robertianum, Lamiastrum galeobdolon and Festuca drymeja shows that these plant communities are a transition between the alliances Luzulo-Fagion and Asperulo-Fagion.

Characteristic taxa.

Distribution in Bulgaria. The acidophilic beech forests have fragmented distributions mainly in Balkan Range, Sredna Gora Mts., Ossogovo Mts., Rhodopi Mts., Belasitsa Mts., North Pirin Mts., Ruy Mts. and Rila Mts.; from 700 to 1700 m alt.

Conservation importance. Acidophilic beech forests in Bulgaria cover about 8500 ha. They play a very important anti-erosion role. The rare species Ilex aquifolium occurs in these forests in Rhodopi Mts. Also the following fungi of conservation significance appear: Cantharellus friesii, Ganoderma pheifferi, Gomphus clavatus, Hericium coralloides, Limacella guttata, Macrotyphula fistulosa, Mutinus caninus, Phylloporus pelletieri, Polyporus umbellatus, Rozites caperatus, Russula solaris, R. violeipes, Strobilomyces strobilaceus, Tylopilus pseudoscaber.

Threats. Unregulated logging, fires, infrastructure constructions, soil erosion.

Conservation measures taken. The habitat is included in Annex №1 of the national Biodiversity Act. Parts of the acidophilic beech forests are within the borders of Rila, Pirin and Central Balkan National Parks, Vrachanski Balkan Nature Park, etc. and in sites of the European Ecological Network NATURA 2000 in Bulgaria: protected zones “West Rhodopi“, “West Balkan Range and Forebalkan“. Part of the acidophilic beech forests have been studied floristically, syntaxonomically and faunistically.

Conservation measures needed. Mapping and monitoring of the most preserved habitats; improvement of the guarding of the forests.

References.Michalik 1985, 1990; Pavlov & Dimitrov 2003; Penev et al. 1969; Tzonev et al. 2006.

Author: Marius Dimitrov


Acidophilic common beech (Fagus sylvatica) forests (distribution map)