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Global climate change also influences the forest damaging agents occurrence and thus a forest health. Forest trees that are damaged by agents are in managed forests processed by salvage felling. The amount of an annual salvage felling represents the occurrence of a damaging agents occurrence in a certain year. In 2015, the area of forests in Slovakia reached 2.014 mil. ha. Within the 20 years (from 1998 to 2017), the total felling reached 162.52 mil. m3, out of this 47.99 % were ascribed to a salvage felling. Abiotic agents were the most damaging agents (42.28 mil. m3 of damaged wood), out of it a wind was the most important one. Biotic damaging agents were the second important group (32.165 mil. m3), whereas bark beetles on spruce were the most important. The third group and the less damaging one was anthropogenic agents group (3.555 mil. m3) with an air pollution as the most important damaging agent. There was no statistically significant difference in the volume of processed trees within salvage felling caused by abiotic and biotic damaging agents. However, these two groups caused significantly higher damages than the third group of anthropogenic damaging agents. There were two major wind damages, Alžbeta in 2004 and Žofia in 2014 with damaged wood 5.3 mil. m3 and 5.2 mil. m3, respectively. They occurred in southern, central and northern part of Slovakia. As damaged wood was not processed from strict nature conservation areas, the secondary damaging agents, mostly Ips typographus on Norway spruce reproduced as much that after some years it cumulatively reached or even exceeded damages from those two major windthrows episodes.

Summary The ability of cotyledons of spruce seedlings to develop their photosynthetic apparatus when grown in the dark was used to study the effect of the «bleaching» herbicide norflurazon (NF) on the formation of their etiochloroplasts. Ultrastructural analyses showed that in etiochloroplasts of cotyledons of 14-day-old seedlings grown in the dark on NF, the number of thylakoids, in particular of grana-thylakoids, was reduced. In plastids resulting after growth on a 200 μmol/L solution of NF, only single thylakoids developed, while in those developed after growth on 20 μmol/L of NF, incomplete stacking of thylakoids appeared. Lower concentrations of NF were less harmful, so that etiochloroplasts with grana regions developed. NF did not influence the formation of prolamellar bodies in the etiochloroplasts. Very strong reduction of carotenoid content, in particular of carotenes and violaxanthin, was obtained after growth of the seedlings in the dark on 200 and 20 μmol/L of NF. At the same time, the content of chlorophylls was also reduced, although to a much lesser degree than that of carotenoids. Analyses of membrane proteins indicated that in these etiochloroplasts the content of polypeptides of LHC II, the major light-harvesting complexes of PS II, was impaired. Only seedlings with less altered plastids were able to develop some photosynthetic activity. High concentrations of NF (200 and 20 μmol/L) caused bleaching of the cotyledons and damage of their plastids when seedlings germinated in the dark were transferred to the light and illuminated for several days.