Abstract: A flail drum system for delimbing and/or debarking small trees and logs has an upper rotary chain flail drum disposed above the path of travel of the wood product and a lower rotary chain flail drum disposed below the path of the product adjacent to the upper drum. Both drums rotate about a generally horizontal axis transverse to the path of travel of the tree or log. Each flail drum assembly includes a central drive shaft and axially spaced apart end rod support members releasably fixed to the shaft. A series of rod support rings have circumferentially spaced openings through which the rods releasably extend to be also releasably received by the end support members. Circumferentially scalloped spacers between the rings, and between the endmost rings and end members, provide radially inwardly extending openings through which the rods pass.