This study presents the results of tool wear and surface roughness of wood processed by plain milling. The tests were done on wood samples of pine and black alder grown in Lithuania in order to clarify time-related tool blunting and the aspects of surface formation. The samples were milled along the fiber in the experimental wood cutting stand at two different cutting and feed speeds. The roughness parameter (Rz) of the processed samples was measured in five sectors along and across the fiber using a contact profilometer. Registered values were analyzed by a Gaussian digital filter and evaluated according to relevant statistics seeking to minimize influence of wood anatomy. The obtained results helped to determine distinctions and variations of surface roughness, which strongly depend on the cutting path, rounding radius of the tool’s cutting edge, cutting, and feed speeds while milling pine and black alder.