The impact of spruce bark beetle populations on mountain spruce forests and ecological approaches to their management

Norway spruce stands represent one of most important forest ecosystems in Central Europe (SK, PL, CZ) both for economic and ecological reasons. This tree species is a dominant component of mountain forest ecosystems that cover a large area of the Carpathian Mountains in Central Europe. The vitality and stability of spruce stands is influenced by a complex of negative factors that provoke their instability and often times their destruction. Several species of spruce bark beetles - Ips typographus, Pityogenes chalcographus, Ips amitinus, Polygraphus polygraphus - play an important negative role in the deterioration and demise of spruce ecosystems, Bark beetle outbreaks have been common and massive in Central Europe during the past 20-30 years. The pre-conditional outbreak phase is always very closely related to predisposing factors that provoke the stress of host trees. There are three important groups of stress factors - anthropogenic, abiotic and biotic. The negative consequences of bark beetle outbreaks on spruce forest ecosystems include environmental effects, forest management problems, economic losses, and societal impacts. Because, these outbreaks have had a very serious impact on nature and on human populations in Central Europe, the countries of Slovakia, Poland and the Czech Republic have focused research on this problem and have developed their own approach to bark beetle population management for two categories of spruce forests - commercial forests and protected forests. At the moment, the systems for management among countries are not fully compatible. For the future, the main goal is to develop a "General plan for the integrated forest protection of spruce stands" that will increase their natural resistance against bark beetle outbreaks. This would be an area-wide management concept that integrates forest protection, silvicultural techniques, forest planning, and ecologically-based harvesting technologies. This approach must be ecologically-based and environmentally friendly.