B. Papp szerk.: Studia Botanica Hungarica 33. 2002 (Budapest, 2002)

Bebya, S.: The fir forests of the Caucasus Mountains and considerations on their preservation

regularities which led to the evolutionary specialisation of the species and to its present distribution, centred on the Colchidean refugium, considerably isolated from other Abies species. The "strategy" of Abies nordmanniana is sufficiently stable within its natural habitats, even on the natural boundary of its distribution. It is a dominating "character tree" of plant communities, and it shows no sign of being influenced by interspecific competition in its communities. This is proven first of all by its high indices of presence in all forest types (100%) and by the phytocenotical index (5400). In all types of forests the renewal continues from Abies to Abies, and we could not detect any changes with accompanying species (BEBYA 1994). Habitat conditions A long process of geological, historical, climatic - first of all hydrothermic conditions, combined with the ecological peculiarities of Abies nordmanniana, as well as anthropogenic influences have resulted in the recent distribution of the Abies forests in the western Caucasus. Specific features of the distribution of the species is determined by the complex influence of these factors (GULISASHVILI 1964). With regard to soils, mainly brown acidic forest soils and brown pseudopodzol forest soils develop under the Abies forests. Differentiation by genetic horizons profile is so subtle that this should be considered one of the distinctive peculiarities of these Abies forests. Both types of soil are fertile enough to support highly productive (up to 2000 mVhectares) Abies nordmanniana and Abies-Fagus stands (ZONN 1950, ORLOV 1951, BEBYA 1999). Regeneration The seed yield of Abies nordmanniana is as usual in the genus: good crop years are followed by 1 or 2 years with very little or no coning. With regard to coning and seed production, the natural fir forests may be grouped into three categories. I) in forests dominated by old trees (over 180 years), 91-94% of the trees are cone producers; II) in forests dominated by middle-aged (121-180 years old) trees, 33-36% of the trees are coning, and III) in those of young trees (age up to 120 years) this value is up to 1% (GIGAURI 1974, BEBYA 2002).