Abstract: The invention relates to a method at the cross-cutting of tree stems to pre-determined timber lengths. According to the invention, an impulse is triggered when the nominal timber length has been attained, which impulse stops the advance movement and braking is effected while the braking energy is accumulated all the way to the stop of the stem after the stem has moved through a certain distance beyond the nominal length. The accumulated braking energy then is released for moving the stem back to substantially the nominal length, whereafter the cross-cutting is carried out. At an apparatus for carrying out the method according to the invention, the feeding wheels (2) of the stem (1) are driven by hydraulic motors (7) having a pressure conduit (5) and a return conduit (6) in common. The return conduit is connected to a pressure accumulator (9). A stop valve (8) is laid-in in each conduit (5,6).