D64: Caucasian pine forests (Pinus kochiana), partly alternating with birch forests (Betula litwinowii, Betula raddeana), and spruce forests (Picea orientalis)

Title

Caucasian pine forests (Pinus kochiana), partly alternating with birch forests (Betula litwinowii, Betula raddeana), and spruce forests (Picea orientalis)

Geographical distribution

Scientific names of main plant communities and their most common synonyms (with author citation)

Pineta hylocomiosa, including Pineta myrtillosa, Pineta oxalidosa, Pineta vacciniosa, Pineta mixto-fruticosa, Pineta rhododendrosa, Pinetum azaleosum (Sosnin, 1939), Pinetum tiliosum (Tumadžanov, 1938).

Structural feature of the main community(ies) (layers, life-forms, etc.)

Pinus kochiana is a typical mountain range tree. It forms communities of different structure depending on site factors, from shrub and open forests to high-stemmed (20-40 m) closed forests. Its main area of distribution is on stonier-rocky mountain slopes at locations high in the mountains where it receives no serious competition from other coniferous or deciduous tree species. On less extreme sites it is often joined by other tree species; depending on altitude, exposure and region: Betula litwinowii, Betula raddeana, Sorbus aucuparia, Abies nordmanniana, Picea orientalis, Fagus sylvatica, Quercus iberica, Quercus macranthera. The species composition of the pine forests varies greatly depending on the microclimatic and geological conditions, and on limestone in particular it reveals numerous endemic species. The second tree layer and the shrub layer consist mostly of broad-leaved woody plants (some summer-green, some evergreen), and are differentiated geographically: At lower altitudes (< 1500 m) oak trees predominate (in eastern Transcaucasia and in Adzharia Quercus iberica, in northern Caucasia Quercus petraea). In northern Caucasia, low-growing Tilia cordata occasionally forms the substratum. At the higher altitudes of the forest belt, Betula litwinowii usually joins the pine, while in northern Caucasia Betula raddeana is also added. In eastern Transcaucasia as well as in the south-east of northern Caucasia there are occasionally pine forests with Quercus macranthera at altitudes greater than 1600m. The herb layer consists of dwarf shrubs, grasses and herbs and is differentiated particularly according to site. On northern slopes it contains sometimes "boreal" coniferous forest species. Mosses are represented in varying strength.

Dominant and most frequent species in different layers

Diagnostically important species

Pinus kochiana, Betula litwinowii, Betula raddeana; Rhododendron caucasicum, Rhododendron luteum, Daphne pontica, Chamaecytisus ruthenicus, Chamaecytisus hirsutissimus, Cistus salviifolius; Carex humilis

Ecological variants

Apart from the typical dry formation types there are also fresh and moist forms as well as types on block and scree slopes.

Geographical variants (geogr. differential species)

The pine forests in northern Caucasia compared to those in Transcaucasia feature boreal species more strongly. At the foot of Mt. Pschegischwa in Abkhazia there are local endemics such as Arctostaphylos caucasica, Daphne woronowii and Sorbus migarica in pine forests, and rarely also Acer hyrcanum. In pine forests on rock slopes in the Abkhazian and Mingrelian limestone mountain ranges calciphilous local endemics occur together with relatively widespread species, such as Genista abchasica, Dioscorea caucasica, Cyclamen purpurascens subsp. ponticum, Daphne pseudosericea, Daphne woronowii, Peucedanum adae, Satureja bzybica, Scabiosa olgae, Centaurea bagadensis, Gentiana paradoxa, Gentiana kolakovskyi.

Natural accompanying vegetation (most important units in complex with the name giving mapping unit, scientific names)

spruce, pine-spruce and spruce-fir forests (Picea orientalis, Abies nordmanniana, D32, D33); birch forests with Betula litwinowii, Betula raddeana.

Adjoining climax and permanent vegetation (with numbers of mapping units)

alpine grasslands (B57), krummholz and open woodlands (C41, C42, C43, C44, C45, C46), fir and mixed fir forests (D32, D33), species-rich Oriental beech forests (F164), hornbeam-oak forests (F167), Stipa steppes (M11), thorn-cushion vegetation (N5).

Land use, substitute communities

Site conditions of the mapping unit

Importance for nature protection

Localities of representative stands (loci typici) with state of protection

Most important references (author, year)

Doluchanov 1992; Grossgejm 1948; Nachucrišvili 1999; Sosnin 1939; Tumadžanov 1938; Tumadžanov 1980

Compiled by

Z. Neuhäuslová based on documents by A.G. Doluchanov; completed by N. Zazanašvili and U. Bohn