On June 15, 2002, about 1130 Alaska daylight time, a tailwheel-equipped Piper PA-12 airplane, N4131M, received substantial damage when it nosed over while landing at an off airport site located about 25 miles northwest of Kenai, Alaska. The solo certificated private pilot was not injured. The airplane was being operated as a visual flight rules (VFR) personal flight under Title 14, CFR Part 91, when the accident occurred. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated at the O'Malley Airstrip, Anchorage, Alaska, about 1000. During a telephone conversation with the National Transportation Safety Board investigator-in-charge on June 16, the pilot reported that just after touchdown, a gust of wind from the left pushed the airplane to the right. The pilot said that in an attempt to realign the airplane, he applied full left rudder, in conjunction with heavy braking action. As the airplane neared the end of the 900 foot long site, the airplane nosed over, and sustained substantial damage to the vertical stabilizer. The pilot said that he applied too much brake pressure in an attempt to stop the airplane before reaching the end of the site. The pilot reported there were no preaccident mechanical problems with the airplane.