The Rodeo-Chediski Wildfire--the largest in Arizona's history--damaged or destroyed ecosystem resources and disrupted ecosystem functioning in a largely mosaic pattern throughout the ponderosa pine (Pinus ponderosa) forests exposed to the burn. Impacts of this wildfire on tree overstories were studied for 5 years (2002 to 2007) on two watersheds in the area burned. One watershed was burned by a high severity (stand-replacing) fire, while the other watershed was burned by a low severity (stand-modifying) fire. In this paper, we focus on the effects of the wildfire on stand structures, post-fire mortality of fire-damaged trees, and stocking of tree reproduction. We also present a fire severity classification system based on the fire-damaged tree crowns and a retrospective description of fire behavior on the two burned watersheds.