39G3

G. Forests

Forests of Grecian juniper (Juniperus excelsa)

Relationships with habitat classifications. EUNIS: G3.932 Peri-Rhodopi Grecian juniper woods; PAL. CLASS.: 42.A32 Peri-Rhodopi Grecian juniper woods; HD 92/43: 9560 *Endemic forests with Juniperus sp.; Bondev (1991): 117 Forests and shrubs of dendroid juniper (Junipereta exelsae), partly the areas are secondarily increased.

Conservation status. BDA, BC, HD.

Category. Critically endangered [CR – A1, 2 B1 B2 C3 D3 E3 F1 G2 H3 I].

General characteristics. The Grecian juniper (Juniperus excelsa) and its phytocoenoses occur in areas with clearly expressed Mediterranean climate – in Rhodopi Mts. near Krichim town (Izgoryaloto Gyune Strict Nature Reserve), Asenovgrad town (very limited along Chepelarska River) and more widely distributed in the valley of Struma River (Kresna Gorge). In Rhodopi Mts. the communities of this species are small and strongly destroyed. In the valley of Struma River, the association Achilleo clypeolatae-Juniperetum excelsae occurs in Kresna Gorge, in the lowest parts of the valleys of Vlahina and Ostavska rivers and in Moravska Protected Site. Small groups or single trees of Grecian juniper can reach to the North to Mechkulska River, between Stara Kresna railway station and Krupnik village. The most representative coenoses are in Tisata Strict Nature Reserve and in its buffer zone. They are “pseudomaquis” – sclerophilic evergreen and deciduous shrubs and small trees with many open places covered with rich herbaceous vegetation. The coenoses of the Grecian juniper occur mainly between 100 and 300–400 m alt. They can reach slightly higher altitudes along the feeders of Struma River where they occupy only the southern slopes of the valleys. Along the light and relatively wide valley of Vlahina river these coenoses reach Vlachi village, while in the narrower and relatively humid valley of Ostavska River they reach lower altitudes. In Kresna Gorge the phytocoenoses of the Grecian juniper cover the eastern and southern slopes on volcanic, often metamorphic, rocks (gneisses, amphibolites). The slope is relatively steep, on average 20–40°. The soils are shallow Leptosols from the subtype Lithic Leptosols. They are strongly eroded and rock pieces of different size occur in many places. Juniperus excelsa is a tree that reaches an average height of 5–6 m. In some places the diameter of the old trees can reach 1 m, but very often these trees wither.

The projective cover of the tree and shrub layer is 30–50%. Of every 10 trees in the locality 2 to 4–5 are Grecian juniper. Other co-dominants in the shrub and tree layers are Carpinus orientalis, Fraxinus ornus and Quercus pubescens. Pistacia terebinthus, Pyrus amygdaliformis are fewer in number, although they may be frequent in many coenoses. The shrub layer is dominated by Paliurus spina-christi and Jniperus oxycedrus. Other species are considerably fewer and occur only in some places, such as Asparagus acutifolius, Coronilla emerus, Jasminum fruticans, Phillyrea latifolia, and Rosa glutinosa. Colutea arborescens and Osyris alba are relatively rare, found only in the lowest parts of the localities. The herbaceous layer is very well developed and has a very rich species diversity. The thermophilic xerophytes of southern or eastern origin prevail. They occur in drier, stony places. Some Pontic-steppe species from class Festuco-Brometea and Festucetalia valesiacae are also typical: Bothriochloa ischaemum(= Dichanthium ischaemum), Chrysopogon gryllus, Teucrium polium, Astragalus onobrychys subsp. chlorocarpus, Eryngium campestre and more rarely Cleistogenes serotina, Goniolimon tataricum, Koeleria nitidula, Sanguisorba minor, Stipa capillata, etc. Typical Mediterranean and sub-Mediterranean species are Alyssum bertolonii, Bromus squarrosus, Clypeola jonthlaspi, Cnicus benedictus, Crupina crupinastrum, Euphorbia barrelieri, E. myrsinites, Hypericum olympicum, Linaria simplex, Onosma echioides, Trifolium smyrnaeum, Thymus atticus, Ziziphora capitata. Balkan endemics and subendemics that participate in the coenoses are Achillea clypeolata, Crucianella graeca, Dianthus gracillis, Galium macedonicum, Trifolium pignathii, Colchicum bivonae, Potentilla regis-borisii.

The phytocoenoses of the association Achilleo clypeolatae-Juniperetum excelsae differ from each other. In some parts where the coenoses are most preserved from the human activities and the participation of the main tree and shrub species is still considerable Aristella bromoides (= Stipa bromoides) in the herbaceous layer and Phillyrea latifolia in the shrub layer still occur (Tisata Strict Nature Reserve and mostly along Vlachina River). These phytocoenoses constitute the typical subassociation. However, in most localities with anthropogenic pressure and advanced erosion more heliophilic and thermophilic herbaceous species occur, including therophytes and hasmophytes (Crucianella graeca, Cynosurus echinatus, Galium macedonicum, Hypericum olympicum, Linaria simplex, Phleum graecum and Senecio vernalis). These coenoses represent the subassociation Phleoteosum graecum. The species composition of the coenoses in Rhodopi Mts. near Krichim and Asenovgrad towns is very similar, especially in the tree and shrub layers (Asparagus acutifolius, Carpinus orientalis, Coronilla emerus, Fraxinus ornus, Jasminum fruticans, Juniperus excelsa, J. oxycedrus, Paliurus spina-cristi, Pistacia terebinthus, Syringa vulgaris). Many common species occur in the herbaceous layer as well: Achillea clypeolata, Aristella bromoides (= Stipa bromoides), Euphorbia myrsinites, Teucrium polium. However, some typical Mediterranean terrophytes are absent but some endemics occur, such as Minuartia rhodopaea and Trachelium rumelianum.

Characteristic taxa.

Distribution in Bulgaria. Valley of Struma River, Kresna Gorge, Rhodopi Mts., the valley of Vacha River to the South of Krichim town, and very limited distribution along Chepelarska River to the South of Asenovgrad town.

Conservation importance. The forests of Juniperus excelsa constitute a rare habitat type throughout the whole distribution area of the species. They develop in very specific conditions of Mediterranean climate and on the steep slopes of deep and rocky ravines. Many rare, endangered and protected plants: Anthemis auriculata, Cachrys alpina, Colchicum bivonae, Crassula tillaea, Delphinium balcanicum, Goniolimon tataricum, Minuartia diljanae, Ononis adenotricha, Ornithogalum oreoides, Sempervivum ciliosum, Trachelium rumelianum, Verbascum roripifolium, and some fungi of conservation importance like Antrodia juniperina, Arrhenia spathulate and Pyrofomes demidofii occur in them.

Threats. Logging, overgrazing, fires, existing roads and paths, electric transmitters, hydroenergy constructions (particularly in the area of Izgoryaloto Gyune Strict Nature Reserve) and other economic activities. Of particular threat is the possible construction of the Struma highway that will pass through Tisata Strict Nature Reserve. This will cause wide destruction of the coenoses of the Grecian juniper. Old juniper trees die due to different reasons: general climate aridisation, parasites (the malt Gelechia senticetella etc.), pollution, forestry activities, etc. The species composition changes due to the invasion of alien species and ruderals in some places.

Conservation measures taken. The habitat is included in Annex № 1 of BDA and is of conservation priority. The Grecian juniper is also included in Annex № 3 of the same Act. The most representative coenoses are within existing protected areas, Tisata and Izgoryaloto Gyune Strict Nature Reserves and in Moravska Protected Site. They are also included in sites of the European Ecological Network NATURA 2000. In order to prevent the withering of the trees some experiments in fighting the pests have been made.

Conservation measures needed. Mapping and monitoring of all coenoses of the Grecian juniper; restoration activities in the damaged localities.

References. Velchev et al. 1984; Stanev 1974; Trifonov2000; Tzonev & Dimitrov 2005.

Authors: Rossen Tzonev, Dimitar Dimitrov


Forests of Grecian juniper (Juniperus excelsa) (distribution map)