Abstract: The present invention relates to a method for sawing a tree trunk and for treating a slice of wood of uniform thickness sawn off the trunk. In the first method, the trunk dimensions and shape as well as the biological quality of each section of the trunk both in the lengthwise and the crosswise direction are defined along with the sawing process, and this information is taken into account while treating the trunk. This method is characterized in that the production programme, which comprises various articles, i.e. product components, of different measures and qualities, is recorded (a) before the actual sawing process. The trunk is sawn into two halves in the middle (b), or the heart slice is removed therefrom (i). The longitudinal quality borders of each trunk half are defined on the basis of the sawn face and recorded (c), and further the shape and size of the trunk half are measured and recorded (d). The quality information and the measuring results are combined (e).