On September 29, 1998, approximately 1700 mountain daylight time, a Cessna 172D, N2479Y, registered to and being flown by a private pilot, was substantially damaged during a loss of control while on the initial takeoff roll at a private, non-identified, turf airstrip near Ronan, Montana. The pilot and his wife were uninjured. Visual meteorological conditions existed and no flight plan had been filed. The flight, which was personal, was to have been operated under 14CFR91, and was destined for Spangle, Washington. The pilot reported that while attempting to execute a soft field takeoff to the south on the turf airstrip, he pulled the aircraft's nose up prematurely. The aircraft then settled back to the surface and the pilot allowed the aircraft to accelerate before pulling the nose up a second time. On this occasion, all three wheels left the surface. Immediately thereafter, while still in ground effect, the aircraft veered left off of the takeoff surface. The pilot reported that he could not maintain directional control, and the aircraft went through a barbed-wire fence, striking several fence posts in the process. Density altitude was approximately 4,792 feet at Missoula, Montana, 40 nautical miles south. In his written response, the pilot recommended that instructors should teach students how to or when to abort bad takeoffs, and to be more aware of those procedures. He stated that he only had one or two seconds to make the decision, and he "made the wrong one."