Abstract: The present invention relates to a process for sawing a log or a block into pieces of lumber, such as blocks, planks, boards, etc. The method is characterized in that pieces of lumber are sawn out with longitudinal cut surfaces such that--when the log is viewed in cross section--the lateral surface of the piece of lumber facing the center of the log is substantially concave while its lateral surface facing away from the center of the log is substantially convex, the concavity and convexity being adapted to the local tangential and radial shrinkage properties of the wood so that the sawn pieces, after drying to the desired moisture ratio, will have substantially plane-parallel sides.