Reforestation OF THE Siberian STONE pine forests AT THE SOUTHERN LIMIT OF THEIR DISTRIBUTION IN WESTERN SIBERIA AFTER THE OUTBREAK foci OF THE SIBERIAN moth
The article is devoted to the research of natural regeneration of the pine forest, which suffered from outbreak foci of Siberian moths<i> Dendrolimus sibiricus </i>Tschetv. The studies were carried out in far south of Tomsk Oblast in the subzone of the subtaiga on the southern border of closed Siberian pine forest area on West Siberian plain in 2011-2015. The results of the research of the dynamic of the undergrowth condition of the Siberian pine forest with different defoliation level of maternal canopy were presented in the article. To assess vitality of the undergrowth of various species, a reference method was used that is based on comparison of morphological inventory indicators of young plants with pre-selected standard items. It was shown that the vitality and survivability of the undergrowth influence the damage level of the tree stands by the Siberian moths. In completely-eaten stands, dark coniferous undergrowth of preliminary reforestation died and broad-leaved trees took up the major portion in the composition of the undergrowth. In the stands of heavily weakened trees the increase in portion of aspen was determined. Under the canopy of the plantation with weak defoliation, the dramatic changes in species composition of the undergrowth did not take place. Prevalence of dark coniferous species is still being observed but its quantity is not enough for successful reforestation. The changes of lighting did not cause either positive or negative reactions of Siberian pines or fir trees undergrowth to an increase in lighting.