The effects of stand density, thinning and pruning on the quality of sawn timber of Scots pine(Pinus sylvestrisL.) were studied based on a computer model. Procedures for the tree growth and crown structure produce a tree, whose properties in terms of location, dimensions and quality (living, dead) of branches are known for any moment of the selected rotation. Consequently, the size, quality (living, dead) and location of knots in sawn timber are recognizable allowing the grading of sawn pieces. The model computations showed that the natural dynamics of the crown system in narrowly‐spaced stands could yield sawn timber nearly of the same quality as resulted from pruning in widely‐spaced stands. Thinning increased the branch growth and the branchiness of the wood yielding lower grade for sawn pieces, respectively.