On July 23, 1993, about 1730 eastern standard time, a Piper PA-28-R200 airplane, N9307N, sustained substantial damage during an attempted takeoff from Dalton Airport, Flushing, Michigan. The private pilot and three passengers aboard were not injured. The personal flight operated in visual meteorological conditions under 14 CFR Part 91. The pilot stated that the airplane lifted-off approximately mid- field. About 50' AGL, he felt the airplane would not be able to clear the trees at the departure end. He elected to perform a precautionary landing on a grassy area next to the runway. The pilot indicated there was no mechanical malfunction with the engine or airplane, but that the engine RPM seemed to be about 150-200 RPM lower after he lifted off than during the takeoff roll. He wrote that the airplane was not climbing very fast. The air temperature at the time of the accident was approximately 85 degrees fahrenheit with a dew point of 72 degrees fahrenheit. Field elevation at the accident site is 733'. The approximate density altitude (uncompensated for humidity) at the time of the accident was 3,300'. A density altitude chart is attached.