Fuel treatments are being implemented on public and private lands across the western United States. Although scientists and managers have an understanding of how fuel treatments can modify potential fire behaviour under modelled conditions, there is limited information on how treatments perform under real wildfire conditions in Sierran mixed conifer forests. The Bell Fire started on 22 September 2005 on the Plumas National Forest, CA. This fire burned upslope into a 1-year old, 158-ha mechanical fuel treatment on private land. Prior to coming into contact with the fuel treatment, the main fire ignited spot fires 400 feet (122 metres) into the treated area. Overall, this fuel treatment resulted in: (1) increased penetration of retardant to surface fuels; (2) improved visual contact between fire crews and the Incident Commander; (3) safe access to the main fire; and (4) quick suppression of spot fires. This treatment was relatively small and isolated from other fuel treatments but resulted in decreased severity, suppression costs and post-fire rehabilitation needs, leading to cost savings for local public and private land managers.