The effect of forest management practices on deadwood resources and structure in protected and managed montane forests during tree-stand reconstruction after dieback of Norway spruce

Abstract

Forest management practices can not only influence the amount of deadwood but also the proportions of particular elements. The goal of the present paper was to compare the amount, number of logs, stumps and snags and their dendrometrical parameters between the protected and managed forests in the Karkonosze Mts after a huge dieback of Picea abies. A massive decline of Norway spruce has been observed since the 1980s. The protected forests belong to Karkonosze National Park and the managed forests are situated in its buffer zone. In total, 1336 elements of coarse woody debris (CWD) were included in the study. They were distributed on 180 study plots (10 m × 10 m) that were randomly selected. Among the deadwood elements, spruce Picea abies dominated (80.3%) followed by beech Fagus sylvatica (14.3%). Logs were more numerous in the protected forest (57.3%) than in the managed forests (42.7%). Snags and stumps were more frequent – 56.9% and 52.8%, respectively, in the managed forests than in the protected forests – 43.1% and 47.2%, respectively. The mean volume of CWD was ca 114 m³ ha^-1 in the protected forests whereas ca 70 m³ ha^-1 was in managed forests.The mean number of stumps per study plot was higher in the managed forests. The mean volume and mean area of logs were higher in the protected forest as was the mean volume and diameter at breast height, whereas the height of the snags was higher in the managed forests. In terms of differences in the decomposition of deadwood between the two types of forests, the mean weighted degree of decay on a five-degree scale amounted to 2.9 in the protected forests and 2.7 in the managed forests. A larger amount of deadwood as well as a greater volume and surface area are very important for nature conservation because deadwood can function as a niche for many saproxylobiont organisms. The forest management practices and especially the weak conditions of spruce lead to a larger number of snags in a managed forest due to the reconstruction of tree-stands and the removal of deadwood by foresters.