Abstract: Apparatus for barking timber, comprising a barking drum and a pretreatment device for patching, that is barking of the timber in spots, the timber is subjected to slashing of its bark in a transverse, longitudinal or oblique direction, this pretreatment device is formed of conveyors and patching members. The conveyors consist of a set of spreading rolls, which spreads the timber longitudinally fed into the pretreatment device to the form of a uniform timber mat, which moves uniformly forward, and of a set of rotating rolls, which transports the pieces of timber and at the same time rotates them about their axes. The patching members previously known in themselves are associated with the set of rotating rolls.