The rate of deadwood decomposition processes in tree stand gaps resulting from bark beetle infestation spots in mountain forests

Decaying wood is an essential element of forest ecosystems and it affects its other components. The aim of our research was to determine the decomposition rate of deadwood in various humidity and thermal conditions in the gaps formed in the montane forest stands. The research was carried out in the Babiogórski National Park. The research plots were marked out in the gaps of the stands, which were formed as a result of bark beetle gradation. Control plots were located in undisturbed stands. The research covered wood of two species – spruce and beech in the form of cubes with dimensions of 50 ​mm × ​50 ​mm × ​22 ​mm. Wood samples were placed directly on the soil surface and subjected to laboratory analysis after 36 months. A significant influence of the wood species and the study plot type on the physicochemical properties of the tested wood samples was found. Wood characteristics strongly correlated with soil moisture. A significantly higher mass decline of wood samples was recorded on the reference study plots, which were characterized by more stable moisture conditions. Poorer decomposition of wood in the gaps regardless of the species is related to lower moisture. The wood species covered by the study differed in the decomposition rate. Spruce wood samples were characterized by a significantly higher decomposition rate compared to beech wood samples. Our research has confirmed that disturbances that lead to the formation of gaps have a direct impact on the decomposition process of deadwood.