THIS CASE WAS REVISED 10/31/2007 On July 20, 20074, at 1458 mountain daylight time, a Cessna A185F (equipped with Aerocet 3400 amphibious floats), N78011, piloted by a commercial pilot, was substantially damaged when the it struck a tree during a forced landing after the airplane failed to climb out of ground effect following takeoff from Runway 17L at Centennial Airport (APA), Englewood, Colorado. Visual meteorological conditions prevailed at the time of the accident. The personal flight was being conducted under the provisions of Title 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. The pilot and two passengers on board the airplane were not injured. The cross-country flight originated at 1504 and was en route to Sturgis (49B), South Dakota. The pilot said he used a normal takeoff technique and rotated 10 knots higher than the recommended POH (Pilot Operating Handbook) speed. He tried "to stay in what little ground effect that was possible...[but] climb performance began to degrade after a few moments." He decided not to continue towards the south, but turned to parallel an interstate highway. During the turn, he had to maneuver the airplane to avoid hitting an overhead sign. The maneuver "scrubbed off enough energy/airspeed" that the pilot "elected to make a precautionary landing" and avoid "possibly stalling the airplane." The pilot landed on an embankment adjacent to the E-470 toll road. During the landing roll, the left wing struck a pine tree near the lift strut, damaging the main spar. Documents submitted by the pilot indicated the airplane was at or near gross weight and was within center of gravity limits. Density altitude was estimated to be between 8,800 and 9,200 feet msl. On September 18, 2007, the pilot examined the engine and found that the compression on No. 2 cylinder was 40/80.