metres. In this zone there is also hybrid fir in small groups and scrubs or small clumps, particularly in the lower region and in the sites Naoumi (west) and Stalamatia and Polykastro (east), where it is mixed with black pine and Bosnian pine. In this zone there is also beech. While in the neighboring mountains Pierians and Ossa it creates an extended vegetation zone, in Olympus it is restricted to small clusters, appearing as islets, mainly in more humid locations and the best soils. A particularly rich variety of trees and shrubs is found in Enipeas' gorge. One can see there elm, cherry plum, European yew, hazel, holly, Cornus mas, manna ash, maple and a considerable variety of herbaceous plants. Gorges and ravines are covered by oriental planes, willows, black alders and riverside greenery. Boreal coniferous zone Typical species of this zone is Bosnian pine. This rare kind of pine occurs sporadically higher than 1,000 metres and gradually replaces the black pine, while over 1,400 metres it creates an almost unmixed forest. Οver 2,000 metres the forest becomes sparser, reaching to 2,750 metres, thus creating one of the highest forest tree line limit (limit of forest growth) in the Balkans and Europe. Another feature of this zone is that over 2,500 metres the trees appear in a crawling form. The region, where Bosnian pine grows, is mostly dry and its slopes are rocky. There are no springs or water streams. The vegetation growing there is adapted to specific local conditions and represented by typical shrubs, graminaceous, chasmophytes etc., while the flora includes many endemic species of the Balkans. Treeless high mountain zone (Alpine tundra) Beyond Bosnian pine's zone follows an extensive zone, without trees, with alpine meadows, consisted by a mosaic of grassland ecosystems, depending on the topography, the slope and the orientation of the ground. In general, this alpine flora with more than 150 plant species, contains snow accumulation meadows, grassy swamps, alpine scree and rock crevices. On the meadows, the rocks and the steep slopes live most of the endemic plants, among them some of the most beautiful wildflowers in Greece. Half of them are found only in the Balkans and 23 only in Olympus and nowhere else. Local endemic plants The list of 23 local endemic plants at Mount Olympus from the Olympus National Park Management Agency: Achillea ambrosiaca, Alyssum handelii, Asprerula muscosa, Aubrieta thessala, Campanula oreadum,