Title
Danubian mixed downy oak-bitter oak–grey oak forests (Quercus pedunculiflora, Quercus cerris, Quercus pubescens, Quercus virgiliana) with Asparagus tenuifolius
Geographical distribution
Country/territory
Romania; Bulgaria: lowlands along the lower Donau
area frequency
9 polygons.
Scientific names of main plant communities and their most common synonyms (with author citation)
Quercetum pedunculiflorae-cerris (Morariu 1944) Popescu et al. 1979, Ceraso mahaleb-Quercetum pubescentis Jakucs & Fekete 1957 (Querceta pubescentis Bondev 1991).
Structural feature of the main community(ies) (layers, life-forms, etc.)
Low-growing, three-layered forests with many Quercetea pubescenti-petraeae species in all layers; steppe like dry grasslands on smaller or larger clearings.
Dominant and most frequent species in different layers
Tree layer
Quercus pedunculiflora, Quercus cerris, Quercus pubescens, Quercus virgiliana, Acer tataricum, Acer campestre, Ulmus minor, Pyrus pyraster, Fraxinus ornus
Shrub layer
Crataegus monogyna, Crataegus pentagyna, Prunus spinosa, Cornus mas, Cotinus coggygria, Euonymus verrucosa
Herb layer
Asparagus tenuifolius, Polygonatum hirtum, Paeonia peregrina, Lithospermum purpurocaeruleum, Viola hirta, Fragaria viridis, Ornithogalum pyrenaicum, Brachypodium sylvaticum, Dactylis polygama, Lathyrus niger, Iris sintenisii (in forest glades: Festuca valesiaca, Chrysopogon gryllus)
Moss layer (incl. lichens)
No details
Diagnostically important species
Quercus pedunculiflora, Quercus cerris, Quercus pubescens, Quercus virgiliana, Acer tataricum, Paeonia peregrina, Carex spicata, Asparagus tenuifolius
Ecological variants
On less dry sites usually Quercus pedunculiflora, Quercus cerris; on drier sites Quercus pubescens, Quercus virgiliana.
Geographical variants (geogr. differential species)
Northern variant to the left of the Danube with less thermophilous species, southern variant to the right of the Danube with more thermophilous species; the number of thermophilous species increases from east to west.
Natural accompanying vegetation (most important units in complex with the name giving mapping unit, scientific names)
Quercion frainetto and Festucetalia valesiacae communities.
Adjoining climax and permanent vegetation (with numbers of mapping units)
oak-mixed hornbeam forests (F49, F68), Balkan oak-bitter oak forests (G20, G21, G22), forest steppes (L12, L13), alluvial forests (U18, U20).
Land use, substitute communities
forestry (substitute communities, plantations of economic tree-species, scrub)
Degraded forests with much Acer tataricum; Ulmus minor stands; Robinia-forestry.
grassland (meadows, pastures, herb-rich communities)
Dry grassland with Festuca valesiaca, Botriochloa ischaemum.
arable land (characteristic weed communities)
No details
settlements (typical ruderal vegetation)
No details
Site conditions of the mapping unit
Landscape type, geomorphology
lowland plains
Altitudinal belt and/or altitudinal range
lowland-colline; 50-200 m
Geology (bedrock)
bluff formation above Tertiary, Cretaceous
soil type, also the depth of fine textured earth (soil), stone content; (international nomenclature)
brown soil-chernozem, red-brown forest soils; (luvic phaeozems; luvic and calcic chernozems; chromic cambisols)
soil moisture, water balance
dry
Climate incl. local climate
climate type (following Walter & Lieth)
VI(VII)
average annual temperature
10-11 °C
average annual precipitation
500-600 mm
average temperature of the warmest month
July 22-23 °C
average temperature of the coldest month
January -2 to 4 °C
local climate or other climatic peculiarities
---
Importance for nature protection
Present state and development trend of natural vegetation (degree of endangerment)
Very few of the earlier forests have been preserved, the small remnants are greatly endangered.
endangered communities, species worthy of protection in natural vegetation
All types of forest are endangered; many species worthy of protection: among them are Paeonia peregrina, Ornithogalum-, orchid-species.
causes of endangerment
Forest grazing, excessive use for low forest management, transformation into arable land.
required measures for protection and restitution
As many of the still remaining well-preserved semi-natural forests as possible should be placed under protection.
Localities of representative stands (loci typici) with state of protection
of the natural vegetation
Romania: Mihai Branu (Giurgiu district), Cringeni (Teleorman district).
of characteristic substitute communities worthy of protection
---
Most important references (author, year)
Bondev 1991; Borza 1966; Gančev 1965a; Gančev 1965b; Morariu 1944; Popescu, Sanda, Doltu & Nedelcu 1984
Compiled by
N. Doniţă based on documents by V. sanda, A. Popescu, I. Bondev
