On September 4, 2004, at 1600 central daylight time, a Johnson-Moore Zenith CH 701, N2077Y, collided with a tree following a loss of directional control while landing to the north on a private airstrip (1,300 feet by 300 feet, dry grass) in Galena, Missouri. The commercial rated pilot received serious injuries. The airplane was substantially damaged. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The flight originated from Aurora, Missouri, approximately 20 minutes prior to the accident. The pilot reported during a telephone interview that after touching down, the airplane made an immediate hard left swerve. The airplane traveled off the left side of the airstrip where it contacted a 12-inch diameter tree. He stated the tree was located approximately 50 yards off the side of the airstrip. The pilot reported the windsock on the airstrip was indicating little to no wind at the time. Approximately one year prior to this accident, the pilot and airplane were involved in a similar occurrence where the airplane veered sharply to the left after touchdown and traveled into tall brush. The pilot stated they inspected the brake system after that occurrence and they did not find any problems with it. He stated they repaired the airplane and he flew it three or four times prior to this accident. Winds reported at the Springfield - Branson Regional Airport (SGF), Springfield, Missouri, located 32 statute miles north of the accident site, about 8 minutes prior to the accident, were from 120 degrees at 10 knots.