Effect of sawmen’ professional experience on working time structure in pine-timber harvesting under conditions of the clear felling. Times of particular operations in timber harvesting with the use of an internal combustion chain saw were analyzed depending on professional experience of the fellers. Investigations were carried out on the two groups of sawmen: of many years’ experience and the beginners in the feller profession. The both groups were compared in consideration of the felling and debranching times. Basing on carried out investigations and their analysis it was found that the percent time structure of operations executed by both the experienced sawmen and the beginners was similar. The longest time was taken by debranching, the shortest time was spent on preparatory and additional operations. However, the experienced sawmen usually execute all the operations in timber harvesting quicker, with the exception of debranching of trees with less branches; here the beginners were more effective.