From the text...'Scope and Method of Study: The response of tallgrass prairie vegetation to headfires and backfires was compared in 1986 and 1987 on a moderately stocked (2.4 AUM ha-1) range 15 km southwest of Stillwater, Oklahoma. Behavior of headfires and backfires was measured using Byram's fireline intensity model and time-temperature relationships. Regression models of fire behavior were developed using environmental parameters as independent variables. Regression models of herbaceous standing crop were developed using environment and fire behavior parameters as independent variables. Findings and Conclusions: Standing crop of tallgrasses in August was 21% (400 kg ha-1) greater on headfired plots than backfired plots. Forb standing crop in August was 26% (98 kg ha-1) greater on backfired plots than headfired plots. Fireline intensity was 10 times greater for headfires than backfires, but there was less difference between headfires and backfires in most time-temperature relationships. Fire type, fuel continuity, fuel loading, and fuel moisture were good predictors of fire behavior. Fire type and fuel moisture were the pre-fire measurement variables most related to standing crop in tallgrass prairie after late spring burning. Time-temperature parameters explained more of the variation of standing crop response to fire than fireline intensity or rate of spread. The area headfired should be maximized within the constraints of the burn prescription on tallgrass prairie managed for livestock. Backfiring in late spring can be used to increase production of forbs for wildlife habitat improvement.'