A lightning-sparked wildfire is burning west of Payson, according to the Tonto National Forest. The Bull Fire was reported Sunday afternoon burning on Bull Mesa in the Mazatzal Wilderness Area, approximately 11 miles west of town. Estimated size Sunday was 50 acres. Officials say smoke may be visible from the Payson area. The Forest Service reported their air-attack plane was patrolling the forest looking for any other new fires sparked by passing thunderstorms.