Title
Northeast Thracian Balkan oak-bitter oak forests (Quercus cerris, Quercus frainetto) with Heptaptera triquetra
Geographical distribution
Country/territory
Bulgaria: foothills of the Balkan mountains in the east (Stara Planina), eastern Tandža-plateau; Turkey: foreland of the Istranca-mountains, south Thrakia
area frequency
6 polygons.
Scientific names of main plant communities and their most common synonyms (with author citation)
Querceta frainetto-cerris Bondev 1991.
Structural feature of the main community(ies) (layers, life-forms, etc.)
Middle to high growing, usually two-layered forests with many thermophilous and also Querco-Fagetea species in the herb layer.
Dominant and most frequent species in different layers
Tree layer
Quercus cerris, Quercus frainetto, with different admixture of Quercus dalechampii, Quercus polycarpa, Ulmus minor, Acer campestre, Acer tataricum, Carpinus orientalis, Carpinus betulus, Sorbus domestica, Sorbus torminalis, Fraxinus ornus, Tilia tomentosa, Tilia begoniifolia
Shrub layer
Crataegus monogyna, Ligustrum vulgare, Cornus mas, Rosa canina, Rosa gallica, Cotinus coggygria, Mespilus germanica, Ruscus aculeatus
Herb layer
Heptaptera triquetra, Ranunculus rumelicus, Leontodon cichoraceus, Doronicum orientale, Silene coronaria, Fritillaria pontica, Primula veris, Viola reichenbachiana, Verbascum phoeniceum, Carex divulsa, Carex muricata, Silene viridiflora, Polygonatum hirtum, Brachypodium pinnatum, Vincetoxicum hirundinaria
Moss layer (incl. lichens)
Hypnum cupressiforme
Diagnostically important species
Quercus cerris, Quercus frainetto, Carpinus orientalis; Heptaptera triquetra, Ranunculus rumelicus, Leontodon cichoraceus, Doronicum orientale, Fritillaria pontica, Ruscus aculeatus
Ecological variants
Different exposures, soil-depths, soil reactions and soil base contents, different water balances.
Geographical variants (geogr. differential species)
In Turkey also with Quercus infectoria, Quercus iberica, Quercus hartwissiana, Fagus sylvatica subsp. orientalis; Erica manipuliflora.
Natural accompanying vegetation (most important units in complex with the name giving mapping unit, scientific names)
oak forests with Quercus pubescens, Quercus virgiliana, Quercus polycarpa; Tilia tomentosa forest on silicate scree slopes in more easily warmed areas.
Adjoining climax and permanent vegetation (with numbers of mapping units)
oak-hornbeam forests (F69), species-rich beech forests (F123), Oriental beech forests (F161, F162), mixed Quercus polycarpa-oak forests (G9), Balkan oak-bitter oak forests (G22), Balkan oak forests (G29, G30), downy oak-bitter oak forests (G31, G32, G33), mixed downy oak-bitter oak-grey oak forests (G34, G35), Oriental hornbeam-downy oak forests (G59, G60), black pine forests (K17), thermo-Mediterranean pine forests (K22), thorn-cushion vegetation (N3), dune vegetation (P14), salt vegetation (P33), alluvial and lowland forests (U18, U36).
Land use, substitute communities
forestry (substitute communities, plantations of economic tree-species, scrub)
Degraded low forest, Carpinus orientalis stands, Paliurus scrub, Pinus forestry, scrub with Juniperus oxycedrus, Crataegus monogyna, Rosa canina, Cistus creticus, Spartium junceum, Arbutus unedo.
grassland (meadows, pastures, herb-rich communities)
Pastures with Chrysopogon gryllus, Bothriochloa ischaemum, Poa bulbosa.
arable land (characteristic weed communities)
Cereals, viniculture and orchards.
settlements (typical ruderal vegetation)
No details
Site conditions of the mapping unit
Landscape type, geomorphology
hilly country and plains
Altitudinal belt and/or altitudinal range
colline-submontane to montane; 30-500 (900) m
Geology (bedrock)
Gneiss, crystal slate, limestone, sandstone-slate (Palaeozoic, Tertiary)
soil type, also the depth of fine textured earth (soil), stone content; (international nomenclature)
intermittent to deep gray-brown podzolic soil, parabrown soils, brown soils; locally ranker, humus carbonate soil, pseudogley-parabrown soils; (chromic and gleyic luvisols; chromic cambisols; leptosols)
soil texture
sandy to clayey loam, loamy clay
soil moisture, water balance
fresh to moderately dry, locally periodically moist
soil reaction
moderately to weakly acidic, locally neutral
soil fertility
mesotrophic, partly meso-eutrophic
Climate incl. local climate
climate type (following Walter & Lieth)
IV(VII), VI2a, VII
average annual temperature
(9) 11-13,5 °C
average annual precipitation
550-600 (850) mm
average temperature of the warmest month
July 22-23 °C
average temperature of the coldest month
January -1 to 0 (2) °C
local climate or other climatic peculiarities
Continental-sub-Mediterranean transition climate, water deficiency in summer.
Importance for nature protection
Present state and development trend of natural vegetation (degree of endangerment)
Strongly degraded and diminished by low forest management and grazing.
endangered communities, species worthy of protection in natural vegetation
No details
causes of endangerment
Low forest use, charcoal production, grazing, clearing, air pollution.
required measures for protection and restitution
Protection of semi-natural stands.
Localities of representative stands (loci typici) with state of protection
of the natural vegetation
Bulgaria: Varbov dol, Kirov dol.
of characteristic substitute communities worthy of protection
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Most important references (author, year)
Bondev 1991; Irmak, Kurter & Kantarcı 1980; Kantarcı 1976; Kantarcı 1978a; Kantarcı 1979a; Kantarcı 1979b; Kantarcı 1980b; Kantarcı 1989a
Compiled by
Z. Neuhäuslová based on documents by I. Bondev
