A plant and a method to produce a panel of multilayer wood fiber consisting of at least three layers, of which one internal core layer (12) and two external layers (11, 13) disposed adjacent to the internal core layer (12) on opposite sides with respect to each other, wherein the internal core layer (12) is formed by recycled wood fiber or by combinations of recycled and virgin wood fiber and the external layers (11, 13) comprise virgin wood fiber.