Eruptive outbreaks of the European spruce bark beetle result in mass attacks of living trees and may cause tree mortality at landscape-levels (Baier, Pennerstorfer & Schopf, 2007). In fact, although this beetle species prefers damaged spruce trees, the beetles also frequently kill solitary spruce trees, for example on the edges of recently harvested clear-cuts (Eriksson, Neuvonen & Roininen, 2007). Under favorable conditions and during an high population level outbreak phase, it is able to attack healthy trees and is a primary factor causing direct tree mortality. Outbreaks can develop rapidly in spruce stands that are damaged by wind, snow, stressed by drought or air pollution (Grodzki, McManus, Knizek et al, 2004). During such outbreaks, the population may increase sufficiently to start an epidemic. In an epidemic situation, spruce bark beetles can overcome the resistance of healthy trees (Joensuu, Heliövaara & Savolainen, 2008). Successful bark beetle establishment is considered to occur in two successive steps. The first step is the tree's defenses are exhausted by pioneer beetles and second, final colonization of the tree occurs (Wermelinger, 2004). The damage by this species causes a decrease in value of the host affected, for instance, by lowering its market price, increasing cost of production, maintenance, or mitigation, or reducing value of property where it is located. In addition, this species may cause loss of markets (domestic or foreign) due to presence and quarantine significant status (Eglitis, 2006). Adults carry a number of associated fungi such as Ceratocystis polonica. This bluestain fungus is highly virulent and can kill healthy spruce trees. In addition, this fungus stains the wood with blue streaks, which reduces its commercial value (CFIA, 2007). Attacked trees die faster than would be expected by solely phloem girdling due to larval feeding. The fungi may dry the tissue and induce tracheid aspiration or vascular plugging (Wermelinger, 2004). The organism is expected to cause significant direct environmental effects, such as extensive ecological disruption. Furthermore, the killing of a large number of trees during outbreaks causes major ecological disruptions resulting in change of tree species composition to non-host trees and increased fuel for high intensity wildfires (Eglitis, 2006). Climate warming, occuring in the past decade or so, allows the bark beetle to complete life cycles at altitudes which were previously unsuitable for its development, and thus may seriously affect the protective functions of mountain forests with regard to rockfall, avalanches and soil erosion in P. abies dominated mountain regions (Seidl, Baier, Rammer et al, 2007). The spruce bark beetle is one pest that could pose significant risk to North American forests if it were introduced. The introduction of this exotic pest could result in significant changes in forest ecosystems, such as tree species conversion, deforestation of riparian communities, increased fuel loading, and loss of biodiversity (Tkacz, 2002).
Location Specific Impacts:
Economic/Livelihoods: Increasing damage in recent years in Central Europe caused an enormous economic impact on forestry due to timber losses and high expenditures for control and sanitation measures (Baier, Pennerstorfer & Schopf, 2007).
Habitat alteration: The Forest Insect and Fungal Damage Prevention Act requires the destruction of many felled trees to help manage the colonization of the european spruce bark beetle, which has led to a very significant decline in the amount of coarse woody debris in managed forests. This development has inevitable consequences for a large number of forest species dependent on dead and decaying wood (Eriksson, Neuvonen & Roininen, 2007).
Economic/Livelihoods: Due to a succession of warm and dry summers, this excessive supply of breeding material induced a major outbreak of european spruce bark beetles resulting in a significant economic loss in timber production (Kreutz, Zimmermann & Vaupel, 2004a).
Ecosystem change: A seven year epidemic in Germany at the end of World War II resulted in a loss of 30 million cubic meters of spruce (Eglitis, 2006).
Ecosystem change: Heavy wind throws in 1993 and climate anomalies provoked the heaviest epidemics of spruce bark beetle in 380 thousand hectares and resulted in the harvesting of 8 million cubic meters of dead trees (Zolubas, 2003).
Economic/Livelihoods: In the 1970s, an outbreak killed 5 million cubic meters of spruce, which led to a substantial reduction of the country's gross national product (Eglitis, 2006).
Ecosystem change: In the 1970s, trees equivalent to 5 million cubic metres of timber were attacked and killed in an area of 140,000 square kilometers (Bakke, 1989).
Reduction in native biodiversity: The outbreak conditions and subsequent mass trapping of bark beetles resulted in some changes in insect populations in Poland (Grodzki, 2004).
Economic/Livelihoods: Norway and Sweden both faced some serious economic losses, as tree killing continued over wide areas (Stenseth & Kirkendall, 2007).
Ecosystem change: An outbreak in Norway and Sweden between 1970 and 1982 following an episode of high winds resulted in a loss of 7 million cubic meters of spruce (Eglitis, 2006).