PAYSON — When lightning ignited chaparral and ponderosa pine litter to form the West Fire in late August, U.S. Forest Service fire managers knew they had some room to let it run. Flames would creep along the brush and undergrowth some 13 miles northeast of Payson, burning around natural firebreaks in the rocks just below the rim. Once the fire crested the rim, having covered some 15,000 acres, it would die against a broader firebreak that Salt River Project (SRP) contractors had chewed out of the dense ponderosa forest with the intention of saving critical Arizona watersheds from just such a fire. …“The intended result is to reduce hazardous fuels, improve watershed conditions and wildlife habitat,” the Forest Service’s incident commander said. …The main reason for thinning, though, is to restore balance and, ultimately, fire itself to a landscape that had grown too thick to burn at less than catastrophic intensity.