37G3

G. Forests

White-barked pine (Pinus heldreichii) forests

Relationships with habitat classifications. EUNIS: G3.616 Rhodopi White-barked pine forests; PAL. CLASS.: 42.716 Rhodopi white-barked pine forests; HD 92/43: 95A0 High oro-Mediterranean pine forests; Bondev (1991): 30 Mediterranean pine (Pinus heldreichii) forests.

Conservation status. BDA, BC, HD.

Category. Vulnerable [VU – A1, 2 B2 C3 D2 F2 G2 1 L2].

General characteristics. Pinus heldreichii is a tertiary relic and a Balkan subendemic. It grows in the Apennines Peninsula (South Italy). The main distribution of the species is in the western part of the Balkan Peninsula in its southern with sub-Mediterranean climate. In Bulgaria it occurs only in Pirin and Slavyanka Mts., from (1300) 1400 up to approx. 2200 m alt. The bedrock is carbonate – marblelized limestone. The species prefers light elevations. Since the species is heliophilic it occupies southern or eastern, and very rarely northern slopes. The areas occupied by these communities most often are steep to very steep, rocky. Under these conditions the xerothermic nature of the habitat is more expressed. More rarely Pinus heldreichii dominates in phytocoenoses established in mezzo- and microdepressions of the relief where the environment is relatively more mesophilic but the ecotope remains rocky. The soils in most cases are stony, neutral or alkaline humus-carbonates including Cambisols. They are well drained.

The communities of Pinus heldreichii are relic, and most of them are monodominant. The participation of other tree species is generally limited. Rarely subdominants can be Pinus sylvestris and Pinus nigra subsp. pallasiana, and even more rarely some tree species the distribution of which is related to silicate: Pinus peuce, Abies alba, Fagus sylvatica. At higher altitudes in the composition of these coenoses can appear also Pinus mugo. Mainly due to the steep slopes and rocky character of the habitat, the projective cover of the tree layer is between 50 and 70%. This increases the light under the tree canopy and hence, a greater diversity of shrub and herbaceous species can participate in the phytocoenoses. However, despite this fact no shrub layer develops. Of all shrub species only the Siberian juniper (Juniperus sibirica) covers up to 20–30% of the surface in some coenoses. Among the remaining shrub species only Chamaecytisus absinthioides and Daphne mezereum and to a certain extent Daphne oleoides occur in a large part of the coenoses, while Cotoneaster nebrodensis, Rubus idaeus, Rosa spp., have more limited distribution. The peculiarities of the habitat in some areas reflect in the phytocoenotic diversity. The most typical representatives of this habitat type are the communities dominated by Festuca penzesii in the ground layer. This species is a Balkan endemic that grows on dry, often shallow and stony soils. In many coenoses another xerophilic species( Brachypodium pinnatum) prevails in the ground layer. Other more frequent herbaceous species are Calamagrostis arundinacea and Poa nemoralis. More rarely dominants are Geranium macrorrhizum or Vaccinium myrtillus. A large number of species prefer the dry and shallow soils of the coenoses under consideration like: Campanula rapunculus, Clynopodium vulgare, Euphorbia cyparissias, Linum capitatum, Minuartia verna, Peucedanum alsaticum, Saxifraga luteoviridis, Scabiosa triniifolia, S. webbiana, Scorzonera rosea, Stachys recta, Thesium bavarum, Thymus striatus etc. Some rare and protected species, including some endemics, also occur like Carum rigidulum subsp. bulgaricum, Saxifraga ferdinandi-coburgi, Verbascum davidoffii etc. In a more mesophytic environment Euphorbia amygdaloides, Galium sylvaticum gr., Geranium macrorrhizum, Luzula sylvatica, Melampyrum sylvaticum, Melica uniflora, Mycelis muralis, Pyrola chlorantha etc. occur. The distribution of some species related mainly to silicate is also possible like Vaccinium myrtillus, Luzula sylvatica etc.

Characteristic taxa.

Distribution in Bulgaria. In Pirin and Slavyanka Mts., on limestone, at (1400) 1600–2200 m alt., in Slavyanka Mts.; up to 2000 m.

Conservation importance. The forests of Pinus heldreichii are very rich in endemic and rare vascular plants – Carum rigidulum subsp. bulgaricum, Kernera saxatilis, Saxifraga ferdinandi-coburgi, Verbascum davidoffii, and rare phytocoenoses of Pinus heldreichii with the participation of Abies alba subsp. borisii-regis, and in Pirin Mts: Hieracium stefanoffii, Laserpitium siler, Polygala acarnanica, Silene heuffelii. Some fungi of conservation importance also occur – Russula amethystina and Sparassis crispa.

Threats. In the past, intensive exploitation or complete cutting of the forests.

Conservation measures taken. The habitat is in Annex № 1 of BDA. A significant part of the habitat is within Bayuvi Dupki – Dzhindzhiritsa Strict Nature Reserve in Pirin National Park, in Alibotush Strict Nature Reserve in Slavyanka Mts. and in sites from the European Ecological Network NATURA 2000.

Conservation measures needed. Monitoring of the habitat state and strict implementation of the law regulations and regimes in the national parks and the norms for nature-friendly forest management. The self-restoration potential of the forests is good and external measures are not necessary.

References. Velchev & Vassilev 1987; Vulchev 2000.

Authors: Vladimir Valchev, Veska Roussakova


White-barked pine (Pinus heldreichii) forests (distribution map)