Abstract: Wood-waste products, such as wood shavings, wood chips and sawdust, are burned in an apparatus having a waste burner comprising an elongated cylinder in which fuel and air are mixed and ignited before entering an enlarged combustion chamber. The waste burner is characterized by an elongated cylinder having a length substantially larger than its diameter so that the fuel can be heated to a temperature sufficient to pyrolyze volatiles and initiate combustion in the cylinder. A wood-waste burner apparatus is also provided and comprises the waste burner of the invention and a combustion chamber for receiving unburned fuel and combustion products emanating from the burner. A process for burning wood-waste products is also provided. The invention is especially well suited for retrofitting packaged boilers to accommodate wood-waste fuels.