A method and a system for handling pieces of timber, wherein data characteristic for a piece of timber obtained by forest harvesting by a harvesting machine (1) is determined by means of equipment (12) arranged on the harvesting machine and is stored in a data base, and the position for the place where the piece of timber is discharged by the harvesting machine (1) is determined by means of position determining means (5) and is stored as position information in a data base associated to the data characteristic for the piece of timber. Said position information is updated, as the piece of timber in connection with subsequent handling is moved by, registering that the piece of timber has been fetched from the place corresponding to the latest stored position information and determining by means of position determinig means (35) the position for the place where the piece of timber is subsequently discharged, the last mentioned position being stored as position information in a data base associated to the data characteristic for the piece of timber.