Abstract

Epidemics of forest insects can have deep impacts on ecosystem functioning and dynamics, with consequences for forest economics and forest carbon feedback to climate change. Despite the many roles that insects fulfil in terrestrial ecosystems, their importance in nutrient cycling is not well known (Kosola et al., 2001). The only instances where herbivores are recognized to have a large effect on ecosystem function are mass outbreaks of particular species like herbivores. However, the climate change induced alterations in precipitation and temperature patterns will undoubtedly affect occurrence, intensity, frequency, magnitude and timing of these phenomena and thus, provoke an increasing susceptibility of hosts and a significantly larger habitat presence of pests. Records show that, in an increasing number of cases severe outbreaks can even cause the complete devastation of vast areas and thus, imply considerable economic losses at a large scale. Down to the present day, it remains uncertain how forest ecosystems will respond to the changing environmental conditions in the long run. This work reports on the possible alterations of forest functions due to mass outbreaks of phytophagous insects with respect to the changing ecosystem service of carbon sequestration ability of forests on the northern hemisphere.

Key words: Forest disturbances, insect mass outbreaks, forest functioning, carbon sequestration.