Fire managers are aware that precommercial thinning increases the fire hazard of a given area, and that resistance-to-control, rate-of-spread (ROS), fire intensity, and ignition potential may also be affected (Appleby 1970, Dell 1975, Dell & Franks 1971, Fahnestock 1968). Thinning slash is additional debris superimposed upon the naturally-fallen fuel that already exists in a stand. In any appraisal of fire hazard and proposed fuel treatment measures, natural residues must be taken into account (Olson & Fahnestock 1955). The question is, 'How much and to what degree does precommercial thinning influence potential fire behavior in a thinned versus unthinned stands?'