Abstract: A system and method to achieve gasification of bark pieces, that includes a vessel to receive the bark pieces which are introduced at an upper region of the vessel and are burned at a lower region, which bark pieces settle from the upper region downward to the lower region in the course of burning and bridge as they settle to leave one or more bypass holes in the bulk thereof. A mechanism is provided to apply angular impelling reciprocating forces to the bark pieces or the like to revolve individual pieces through acute angles, first in one direction and then in the other, to disrupt the bridging and hence the bypass holes.