A company needs to know what it knows and how to take care of this knowledge. The way forest knowledge is handled within a forest company is a means to turn knowledge into a source of competitive advantage. Forest data and its information are important parts of the forest planning. The aim of this study is to describe and analyze how forest knowledge is used for timber production planning in a large forest owning company in Sweden. The study is conducted as a case study at Sveaskog - the largest forest owning company in Sweden. Concepts and theories from knowledge management are used. The study is limited to present the forest planning process from the long term felling strategy until the stands are transferred to the tract bank. Interviews with key persons within the organization were used to capture how forest knowledge is used. The information is presented through the four knowledge management processes: creation, storageretrieving, transferring and applying. The planning system relies to a great extent on codified knowledge realized through a push strategy. It appears that the system works as a consistent whole.