This thesis presents the yields from timber when sawing spruce logs of different diameters. The types and quantities of the various finished products obtained from such mechanical processing are also important. It was found that, in certain cases, the yields from timber assortments when sawing were very high, even over 80%, and the yields from the total trunks were up to nearly 80%. The degree of taper, as an error of the logs, does not always have a negative effect on the yield, and, in some cases, may even be higher than the low level of taper. The yield is largely and mostly influenced by the machine operator`s experience, the types of sawmill products, and the dimensions of the assortments. With sawn wood, the posts, planks and beams predominate, while the laths, strips, and boards are presented in smaller proportions. In terms of quantity, the amount of sawdust left over from cutting logs is presented to be approximately 10%. In most cases, when the diameter increases, the average thickness of the bark increases. The amount of bark on a log varies according to the diameter and, in our case, amounts to 6-8%.