Morphological forms of siberian stone pine trees (Pinus sibirica Du Tour) in high altitudinal forests of Severo-Chuisky range: 1. Morphological aspect

In the upper forest belt in Altai Mountains, Russia, the coniferous species are the main forest-forming trees. Their living form is straight-stemmed trunk tree. Moving to the climatic lines, individuals of the transition living morphological forms of these species appear in the forest belt. The most diversity of the forms is in the forest-tundra ecotone. We describe the morphological forms of Pinus sibirica Du Tour growing at the upper forest belt in the headwater Aktru, Severo-Chuisky Range, the Altai Mountains. The main living form of Pinus sibirica is tree (straight-stemmed or lean-stemmed trunk, one- or multi-stemmed, one- or multi-top tree) in forest communities here. The basis of its crown is branches of primary crown. The secondary crown do not develop. The transition morphological forms are here: tree or stumps with power candelabra branches, "living" windfallen trees, elfin wood form in the tree butt of the straight-stemmed trunk tree, and shrub-like form. The elbow of the candelabra branch can be produced by both orthotropic growth of the second order branch on first order branch and the elbow of the first order branch. The shrub-like form is formed by an enlargement of the first order branches which are located at the butt of small trees since decline of their top. The elfin wood form grows at the tree butt between buttress flares of the mother tree. The distal part of the form can transform from plagiotropic growth to orthotropic. In fallen trees (if one or some roots and xylem strand are living) some branches change previous growth on orthotropic. All the forms can bear cones for several decades and root if contact with soil. The following conditions and factors promote production of these morphological forms: great insolation, abrupt difference of day and interseasonal temperatures, debris flows, avalanches, stone soil, its grade, firm red heart, shallow root system, and contact of the branches with mellow and moist soil. Such forms often locate in open communities and on glades and at edges in close communities. In one Siberian stone pine individual the combination of the main living form and related with it the morphological structures that are potentially the following vegetative generations can be considered as one of adaptations for sellf-maintenance of the Pinus sibirica populations.

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