On July 17, 2005, approximately 1000 mountain daylight time, a Piper PA-18-150, N721JW, impacted a tree during the takeoff roll at Vines Airstrip, Yellow Pine, Idaho. The private pilot was not injured, but the aircraft, which is owned and operated by the pilot, sustained substantial damage. The 14 CFR Part 91 personal pleasure flight, which was departing for McCall, Idaho, was being operated in visual meteorological conditions. No flight plan had been filed. According to the pilot, during the takeoff roll at the remote grass airstrip, the right main landing gear hit a mound of dirt created by a burrowing animal, and the aircraft suddenly veered to the right. The pilot applied left rudder to correct the situation, but he was unable to get the aircraft back on takeoff heading prior to it departing the right side of the airstrip surface. Soon after departing the takeoff surface, the aircraft's landing gear rolled over some nearby large rocks, and the right wing impacted a tree that was located near the side of the airstrip. In a telephone discussion with the NTSB Investigator, the pilot said that he did not see the dirt mound during the takeoff roll because it was hidden by tall grass/weeds. When asked if he had walked the length of the 1,100 foot remote runway looking for obstructions prior to takeoff, he said he had not. According to a note in the Idaho Airports Guide, the surface of this runway is rough and subject to ongoing deterioration, and its usage is limited to "highly experienced" mountain pilots.