Problem masowego zamierania drzewostanów świerkowych w Leśnym Kompleksie Promocyjnym "Puszcza Białowieska"

The Białowieża Forest (BF) is in many respects an exceptional object, of a great importance for nature protection and forest management, at the international scale. The BF plays also a key role from the point of view of regional development and welfare of local community. In the last period, a big threat for multiple values of the BF has arisen, as a result of enormous bark beetle infestation, which started in 2012 and has killed 1.4 million m3 of spruce trees. In the paper, first, a brief overview of the general history of the BF and an account of long−term human impacts on its functioning and structure is provided. Next, the history of bark beetle infestations in the BF is analysed. It is shown that, in the period 1992−2007, the average volume of spruces killed by bark beetle amounted on average to 20,000 m3 of wood annually. During that period practically all dead trees were removed from the forest by means of salvation cuttings. Starting from 2008, more and more trees infested by European spruce bark beetle were left in the forest, in a result of a pressure exerted by environmental groups. In 2012, Minister of Environment decided to reduce the allowable cut, determined in forest management plans elaborated for the managed part of the BF, from 107,000 to 48,500 m3/year. This decision, along with several other regulations and restrictions, made in practice impossible to stop the development of a current bark beetle infestation, which started in 2011 and intensified during the next 6 years (solely in 2016 bark beetles killed 480,000 m3 of spruce trees). In the paper, the most important implications and consequences of the current situation are briefly summarized and discussed. A special attention is given to the problems concerning: 1) protection of Natura 2000 species and sites (endangered by bark beetle outbreak), 2) a negative influence of large amounts of spruce deadwood on forest soils, 3) threats caused by pathogenic fungi, 4) question of public safety, 5) fire hazard, and 6) economical dimension. The legal and socio−economical foundations of the functioning of Hajnówka, Browsk and Białowieża forest districts comprising the managed part of the BF, as well as their most important environmental and social consequences are discussed too. Among others, it is indicated that, under current conditions of the BF, human intervention plays a key role in maintaining stable and compositionally diverse woodland communities. Finally, several suggestions and recommendations are provided, aimed at, in the short term, breaking off the current bark beetle outbreak, and, in the long term, at maintaining a multifunctional character of the BF and its ability to provide all important ecosystem services on a sustainable basis.