Wpływ gradacji kornika drukarza na zagrożenie pożarowe Puszczy Białowieskiej

The Białowieża Forest, considered as the last primeval forest on the European Plain and in Poland mostly known as the oldest national park, in recent years has faced the bark beetle (Ips typographus) infestation located mostly in its managed part of three forest districts: Białowieża, Browsk and Hajnówka. Undertaken protection measures, mostly consisted of dead and infested trees removal, has induced the dispute regarding the question whether man should actively counteract the degradation of precious habitats or just passively observe the nature left alone. Even the European Court of Justice has stated that besides emergency situations and absolute necessity to ensure safety for citizens all trees removal must be suspended until the end of dispute. The succession of the bark beetle infestation is manifested by the increase of forest fire risk due to the large amount of dead wood (before the infestation it was around 24.9 m3/ha and in 2017 it increased up to 231.8 m3/ha). Due to the forest stands disintegration and canopy openness grass cover has spread over 10 000 ha – when dried it stimulates the origin and development of the fire. Before 2012, in the middle of which the infestation begun, the Białowieża Forest was protected by con− ventional forest fire protection system according to the actual forest fire risk degree. In the framework of the project ‘The development of the fire protection rules for the protected objects and the use of the prescribed burning as an active method of nature protection’ ordered by the General Directorate of the State Forests National Forest Holding, forest fire risk analysis was taken after the infestation of bark beetle. That was the base for the modification of forest fire protection system including current risk. The amount of the dead wood, its size and the decomposition stage as well as type of the soil cover were taken into consideration together with the data derived from dead wood inventory in years 2016−2017 (based on the 1400 sample plots, 400 m2 each), annual dead wood inventory conducted by forest districts and own research regarding fuel load (amount of the biomass according to the area unit).