An oven has an enclosed heat exchange zone for use with biomass fuel. The oven has a body which is able to be placed on the ground. The body has a combustion cabinet and an auxiliary equipment cabinet. The combustion cabinet has a burner received therein. The burner has a fire grate, a side plate, a blowing space, and a hearth. A heat exchange zone is defined by the surrounding tubular inner wall; a side heating zone being defined by a tubular inner and a tubular outer walls. A chimney is formed on the tubular outer wall in communication with an upper portion of the side heating zone. An opening is defined in the top of the combustion cabinet right above the tubular inner wall.