Abstracts

Forest Ecosystems

Cutting with the use of aggregate equipment as well as bioecological characteristics of dark-conifer species and their growing in fertile soils (fresh and damp fertile soils), with a cover of long-stalked grasses, cause slow regeneration of destroyed dark-conifer stands and formation of meadow cenosis or low-dense birch-asp stands with rare understory coniferous trees. At the borders of cutting areas, at the undercut areas during the additional nutrition concentration of Monochamus urussovi and its distribution on the nearby forest range occur. Other factor that causes destruction of cedar, fir, spruce stands is the influence of mass proliferation of conifer-chewing insects (first of all Dendrolimus sibiricus). The damaged stands lose their biological stability and become areas where processes causing change of vegetative and animal communities happen, sometimes up to complete disappearance of forest on vast territories (such processes as swamp and steppe formation). In the forests damaged by the Siberian silkworm, forests regeneration starts after the complete renewal of species. Fires (especially while burning out the basic stock of deadfall) slow down processes of regeneration, even by deciduous species. Besides that Dendrolimus sibiricus and cutover areas are a significant factor of destabilization of forest ecosystems of a region, which influences on the development of outbreaks of insect propagation (Monochamus urussovi), and that leads to even greater consequences.

To collect the long-term information (more than 150 years) about a natural life cycle of Dendrolimus sibiricus were used dendrochronological data obtained in isolated from fire old dark-conifer forest areas. Taking into account long (about 100 years) preservation of trunks (stubs) of Pinus cembra sibirica, it is possible to use them in researches to define the period of destruction of a forest stand (cross dating).

Computer modelling of the structural and functional organization and dynamics of dark-conifer ecosystems is carried out with the use of modern information technologies (geoinformation systems, neuronic networks etc.). Attributive databases are formed on a basis of forest management materials and dendrochronological data.

Regularity observed in situations when new centers of Dendrolimus sibiricus adjoin the old centers confirms a hypothesis about prevailing role of a silkworm in cyclicity of development of dark-conifer forests of Siberia.

Use of the long-term data for successions studying will allow to model dynamics of forest ecosystems and to render possible allowable influence.

Note. Abstracts are published in author's edition

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