Include here is northern Greece (including the Pindos Mountains), parts of Albania, Macedonia, Bosnia-Herzegovina, Croatia, Slovenia (including the Karawanken and Julian Alps), but not the Adriatic coastal areas of these states. Its northeastern boundary runs mostly along the valley of the River Sava and continues along the Danube River to include most of Bulgaria with the exception of its northeastern steppe regions. In the southeast it extends into European Turkey. Also included is the so-called Pannonic zone named after the old Roman province of Pannonia, which is a western enclave of the steppe region and centred on the Hungarian Plain but also includes southern Romania and northern Bulgaria. In fact, it forms a corridor of lowlands along either side of the Danube River to the northwestern coast of the Black Sea. At least two forest types have have been recognised.

Balkan Mixed Deciduous Forest

These forests vary enormously but usually include a variety of oak species such as Quercus cerris, Q. frainetto, Q. robur and Q. sessiliflora, and other broadleaved species like Acer campestris, Carpinus betulus, Castanea sative, Juglans regia, Ostrya carpinifolia and Tilia tomentosa.

Balkan (Pannonic) Oak Woodland

Fragments of woodland dominated mainly by different species of oak occur across the Pannonic zone. The most important species are Quercus cerris (Turkey oak), Q. frainetto (Hungarian oak) and Q. pubescens (White oak), but other species such as Q dalechampii, Q pedunculiflora and Q. polycarpa may also be encountered. Other characteristic trees are Acer tataricum, Carpinus betulus, C. orientalis, Tilia tomentosus and the endemic Fraxinus angustifolium subsp. pannonica (Oleaceae). Many of the canopy trees are deciduous and in the more natural examples the canopy tends to be very dense. Consequently, ground vegetation is at its best during springtime. Shrub layer species vary but may include Cotinus coggygria, Cornus mas, Euonymus verrucosus, Prunus mahaleb and Staphylea pinnata. Likewise the field layer varies but typical species may include Acillea coarctata, Ajuga laxmannii, Buglossoides purpurocaerulea, Helleborus odorus, Lathyrus pannonicus and the near endemic Cynoglossum hungaricum (Boraginaceae).

References

Horvat, I, Glavac, V & Ellenberg, H. 1974. Vegetation of Southeast Europe. Gustav Fischer Verlag. Stuttgart.

Polunin, O. 1980. Flowers of Greece and the Balkans. Oxford University Press.

Turrill, W. B. 1929. The Plant life of the Balkan Peninsula - a phytogeographical study. Oxford.

Webb, D. A. 1966. The Flora of European Turkey. Proceedings of the Royal Irish Academy, 6: 1-100.