On October 2, 2004, about 0955 mountain daylight time, a Cessna 150G airplane, N3086R, sustained substantial damage after colliding with trees and terrain shortly after takeoff from the Benchmark Airport (3U7), Augusta, Montana. The airplane is owned by the passenger and was being operated as a visual flight rules (VFR) personal/pleasure flight under Title 14, CFR Part 91, when the accident occurred. The private pilot and passenger sustained minor injuries in the accident. Visual meteorological conditions prevailed, and no flight plan was filed for the flight. In a written statement the pilot reported the airplane collided with trees and rising terrain shortly after departing runway 12 at Benchmark. The pilot reported the airplane cleared trees (approximately 50 feet in height) located at the end of the departure runway, however, the aircraft made contact with multiple trees and rising terrain beyond the departure end of the runway. The pilot stated "we hit trees for 150 yards before slowing enough to hit the ground." The published airport elevation for Benchmark is 5,434 feet MSL. The pilot reported that the outside air temperature at the time of the accident was 34 degrees Fahrenheit. No mechanical malfunctions or failures that may have contributed to the accident were reported.