The pilot reported that, during takeoff on a grass runway, after lift-off, he noticed he was not able to climb at a normal rate. He lowered the nose of the airplane, but the airspeed remained "dangerously low" and the stall horn sounded intermittently. He reduced power to abort the takeoff, but there was insufficient runway remaining. The airplane touched down, overran the runway, the left wing impacted a tree, and the airplane spun 180° before coming to rest. The airplane sustained substantial damage to the left wing. The automated weather observation station located on the airport reported that, about 5 minutes after the accident, the wind was from 140° at 5 knots, temperature 64°F, dew point 59°F. The airplane was departing on runway 26. The pilot did not submit the NTSB Form 6120.1 Pilot/Operator Aircraft Accident/Incident Report.