Abstract: In a delimbing device for a tree processing apparatus (10), comprising a pair of curved gripping means (22, 26) provided with limbing knives (24, 28) and adjustable by actuator means (44, 46) for supporting and delimbing a peripheral section of a tree trunk movable in the longitudinal direction and preferably towards the top end thereof relative to the gripping means, and comprising an additioinal limbing knife (36) movably biassed against the tree trunk for delimbing a remaining peripheral section thereof, there is suggested, in order to maintain the close contact of the limbing knives around the trunk during the limbing operation, that position sensor means (64) are arranged to emit a signal for adjustment of said actuator means (44, 46) to change the amount of closing of said gripping means (22, 26) and to thereby change the position of the tree trunk in the processing apparatus (10), each time a section of the trunk facing the additional limbing knife (36) has been displaced a predetermined distance in th