A study of 183 sample plots in the Niepołomice Forest District was conducted to determine the impact of timber extraction during incidental felling and thinning on the type and amount of deadwood left to decay naturally in the forest. Deadwood was measured and classified as logs or snags, and three types of forests stand were distinguished: coniferous, oak-hornbeam, and black alder swamp forest. The amount of timber harvested in 2010–2015 in 365 selected forest compartments was grouped according to 14 types of silviculture practice. A large amount of timber was extracted during incidental felling as well as thinning, when dead and dying trees were cut and partially extracted from the forest. Harvesting intensity was positively correlated with the amount of logs only in the less accessible black alder forests. In oak-hornbeam forest, the more timber extracted, the lower the amount of deadwood present. To increase the volume of deadwood and lower the economic loss, timber extraction during incidental felling and thinning should be limited.