The Role of Forest Stands Characteristics on Formation of Exterior Migratory Outbreak Spots by the Siberian Silk Moth Dendrolimus sibiricus (Tschetv.) during Population Collapse

The characteristics of Abies sibirica Ledeb.- and Pinus Du Tour dominated forests stands in outbreak spots formed during a Dendrolimus sibiricus 2014–2017 were studied at the stage population collapse (east West Siberian Plain western foothills Yenisei Range). research was based on data obtained ground surveys conducted 2016 when characteristics, silk moth density, defoliation level recorded. We classified using decision trees random forest algorithms to identify key that determine formation spots. classification results showed detected differ significantly from those previously described for dark coniferous southern taiga Siberia. highest probability spot occurrence study area revealed with following characteristics: moderately moist site; stone pine fir take 40% or more stem volume; age less than 105 years. Another group under threat are sharing large (more 60 ha); stand homogeneity; vegetation is by feather mosses; 120 years; Picea obovata Ledeb. takes significant share volume. Such indicate collapse, forms either undergo an early successional after previous have been slightly damaged outbreaks due unfavorable habitat conditions.