Abstract: The invention is a heating panel (10) for treating wood material (22), comprising two boundary members (12) arranged parallel to each other, and a heating wire (14) arranged between the boundary members (12). The heating panel (10) is characterised in that the heating panel (10) further comprises a solidified wood treatment composition (16) arranged between the boundary members (12) and surrounding the heating wire (14), and the boundary members (12) are configured to allow the solidified wood treatment composition (16) to contact the wood material (22) to be treated. The invention is furthermore a treatment apparatus (20), and a method for treating wood material (22).