A harvester head (1), comprising a frame part (10) and tree processing means (2, 3, 4, 5) for gripping a tree trunk (T), for feeding the tree trunk (T) in a longitudinal direction, for debarking and for cross cutting the tree trunk. The harvester head (1) is adapted for processing at least two trees (T) simultaneously, the harvester head is provided with a collector arm (23) of dual function, both gripping function for gripping and holding a tree (T) during a collecting phase and debarking function, the collector arm (23) is provided with a debarking knife (30) for debarking at least two consequently collected trees (T) at an area between the two trees (T). The invention relates also to a corresponding method in processing at least two tree trunks simultaneously with a harvester head.
