Relationships with habitat classifications. EUNIS: G1.7D1 Helleno-Balkan chestnut forests; PAL. CLASS.: 41.91 Helleno-Balkan chestnut forests; HD 92/43: 9260 Castanea sativa woods; Bondev (1991): 52 Ordinary chestnut (Castaneeta sativae) forests.
Conservation status. NDA, HD.
Category. Endangered [EN – A1, 2 B1 C2 D2 E2 F2 G2 H2 I J L2].
General characteristics. The habitat encompasses the mesophytic and xeromesophytic forests dominated by or with the participation of the chestnut (Castanea sativa). They occur mainly in Belasitsa, Slavyanka and Ograzhden Mts. and the Balkan Range (Berkovitsa Mts.). They occur in the hornbeam-sessile oak belt from 300 up to 1150 m (optimal altitude 400–700 m) on slopes with different slant, mainly in shadowy places and at moderate, relatively humid climate conditions. The typical soil cover develops mainly on silicate and is represented mainly by Dystric Cambisols, Umbric Leptosols and Lithic Leptosols and more rarely by Eutric Cambisols and Haplic Luvisols. The chestnut forests are usually with well preserved vertical and horizontal structure.As co-dominants in the tree layer are the species Acer campestre, A. pseudoplatanus, A. tataricum, Betula pendula, Carpinus betulus, Fagus sylvatica, Platanus orientalis, Populus tremula, Quercus dalechampii, Q. frainetto (in the more southern places), Tilia platyphyllos, T. tomentosa etc. The understory consists of Corylus avellana, Cornus mas, C. sanguinea, Crataegus monogyna, Euonymus europaeus, Ligustrum vulgare, Rubus hirtus etc. The herbaceous layer consists of spring (Crocus pulchellus, Colchicum autumnale, Corydalis solida, Cyclamen hederifolium, Primula veris, P. vulgaris, Scilla bifolia etc.) and summer (Euphorbia amygdaloides, Lathyrus laxiflorus, Luzula luzuloides, Melica uniflora, Mycelis muralis, Pteridium aquilinum etc.) synusia. There is a contact zone between the plantain (Platanus orientalis) and chestnut coenoses in Belasitsa Mts.
As a result of the climatic factors and intensive forestry activities the chestnut forests turn into coenoses dominated by the beech (Fagus sylvatica) and hornbeam (Carpinus betulus). This is due to the invasion of skiophytic deciduous species and degradation processes – dry tree tops, defoliation, withering, development of semiparasites (Loranthus europaeus), diseases (mass development of Cryphonectria parasitica that causes cancer in chestnut trees, Melanconis modonia that causes the ink disease, etc.). This tendency is typical for the coenoses that are outside the ecological optimum of the species.
Syntaxonomically the chestnut forests belong to class Quercetea robori-petraeae, order Quercetalia robori-petraeae, alliance Quercion robori-petraeae and association Castanetum sativae (macedonicum). The subassociation fagetosum of the same association has been established in Belasitsa Mts.
Distribution in Bulgaria. Northern slopes of Belasitsa and Slavyanka Mts., (above Petrovo village, on silicate), southern slopes of Ograzhden Mts. (the valleys of Gradeshnitsa and Ribnishka rivers), Pirin Mts. (northern slopes near Brezhani village and Gotse Delchev town) and West Balkan Range – near Berkovitsa town. The chestnut forests cover a total area of about 3000 ha.
Conservation importance. The chestnut forests are of relic origin. Many vascular plants of conservation importance occur in them: Dactylorhiza incarnata, Ilex aquifolium, Juniperus excelsa, Limodorum abortivum, Medicago carstiensis, Platanthera chlorantha etc., as well as the fungi of conservation significance – Amanita caesarea,Boletus luteocupreus.
Threats. Natural degradation successions the intensity of which is increased by direct (grazing, logging for wood exploitation, cutting and thrashing of the branches to collect the fruits, and for “rejuvenating” of the trees for higher fruit yeld, etc.) and indirect (tourist pressure, pollution, deceases and pests etc.) anthropogenic factors.
Conservation measures taken. The habitat is included in Annex № 1 of BDA. Parts of the forests are within protected areas: Kongura and Alibotush Strict Nature Reserves, Belasitsa Nature Park and in sites from the European Ecological Network NATURA 2000. The species is included in the Red Data Book of Bulgaria. An inventory of the plant resources of the chestnut forests has been conducted.
Conservation measures needed. Monitoring of the state of the habitat, elaboration of forestry schemes for sustainable management and maintenance of an optimal structure of the chestnut forests; preservation of good health state; prevention of degradation, fragmentation and destruction of the coenoses.
References. Bratanova et al. 2005; Dimitrova et al. 2007; Glushkova 2005; Kochev 1973; Lyubenova et al. 2002, 2004; Michaylov 2003.
Authors: Mariyana Lyubenova, Svetla Bratanova