A method and a control circuit for an apparatus, comprising at least a first motor (18-21, 32-33) which is configured to drive a feeding device for feeding a tree trunk through the apparatus, and a first valve assembly (11) configured to control the rotation of the first motor by means of pressurized pressure medium. The control circuit also comprises a second valve assembly (45) configured to supply or convey pressure medium to the first motor (18-21, 32-33), whereby it is possible to maintain a predetermined pressure level of the pressure medium in the first motor, or pressure medium is available for the first motor. In an example, the apparatus is a harvester head comprising said control circuit.
