Ukrainian forests degradation: current state, mass drying reasons and ways of its prevention

Abstract

The current significant deterioration of the sanitary state and the degradation of Ukraine's forests is conditioned by massive dieback of trees and stands of pine and other forest species in conditions of global warming. It is urgent to carry out organizational measures and works to improve the biological stability of future forest ecosystems during the whole process of their cultivation, starting from the moment of their natural or artificial regeneration.

Trees and stands dieback was observed earlier in the 19 and 20 centuries, but in most cases it occurred at the regional level. However, since 1970 in many countries dieback has been observed on large areas. In such a case different reasons are called as trees and stands dieback factors: climate change, groundwater reduction, pests and pathogens harmful activity etc.

Goal of research – based on literature data and own research results to establish and substantiate etiology and pathogenesis of massive dieback of trees and forest-forming species stands, in particular, pine stands, and to propose strategy and tactics for preventing this negative natural phenomenon.

During program tasks implementation a number of scientific papers, where various aspects of massive dieback of trees and stands were highlighted, have been analyzed. Basic theoretical positions and practical recommendations outlined in the article are based on the results of our own research on oak stands dieback in Kyiv green zone in the 1980s and current pine dieback in Polissya.

The research has allowed us to offer our own concept on this negative natural phenomenon etiology and pathogenesis. All the highlighted drying factors according to peculiarities, activity sequence and their specific meaning were combined into three groups: 1. Weakening circumstances and risk factors for disease. 2. Etiofactors or dieback origin. 3. Trees and stands dieback catalysts. Generalization and studying all factors take into account global warming. This has allowed proposing measures to improve the biological sustainability of future forests at the stage of their regeneration.

Understanding and using the abovementioned statements on etiology and pathogenesis of trees and stands of forest-forming species mass dieback will allow to preventively apply scientifically based silvicultural measures that exclude the above mentioned weakening and risk circumstances and, thereby, to prevent the prime cause of the harmful effects. This will allow minimizing negative consequences of pathogenesis and reduce possible resource, environmental and social losses.

Keywords: massive dieback, stand, etiology, pathogenesis, etiofactors.