Key methodological approaches to assess eco-system services in foreign states: overview of the problem

The paper presents analytical materials on publications covering forest eco-system services assessment in foreign states. Over the last 20 years forest eco-system service studies in foreign states are characterized by exponential growth of publication activity. Basic classifications and key approaches to assess eco-system services in foreign states are available. International and national processes and programs in eco-system service area are reviewed. Research areas and practical applications of forest eco-system service assessments as a major and integral part of ground ecosystem in general are already shaped now.