THE REDUCTION OF RESISTANCE OF CONIFER FORESTS IN SIBERIA TO ROOT PATHOGENS AS A RESULT OF THE MODERN AIR AND GROUND TEMPERTURE INCREASE

Ground temperature increase, which happens faster than air temperature increase, is considered to be one of the causes that promote root rot diseases (and first of all, Armillaria mellea s.l.) resulting in massive conifer forest decline in South Siberia. Temperature soil condition becomes more favorable for mycelium growth for a longer vegetative period. In autumn, while soil conditions are still favorable for root pathogen growth, the tree crown and trunk are in lower temperature, which negatively af- fects the protection mechanisms (including secretion of soft resin) against Armillaria mellea s.l. and Heterobasidion annosum s.l. invasion.