On March 1, 2006, about 1240 eastern standard time, a Mooney M-20J, N511G, registered to and operated by a private individual, as a Title 14 CFR part 91 personal flight, incurred a loss of engine power while climbing to cruise altitude, and the pilot made a forced landing in Fort Pierce Florida. Visual meteorological conditions prevailed, and no flight plan was filed. The private-rated pilot received minor injuries, and the airplane incurred substantial damage. The flight originated in Fort Pierce, Florida, the same day, about 1230. According to the pilot, about 8 to 10 minutes after takeoff, while still climbing, at an altitude of about 5,000 feet, the airplane lost engine power. The pilot further stated that the gauges showed about 1,000 rpm, and the manifold pressure remained at 25 inches. He said he operated the throttle, and observed instruments while attempting to regain power, but he could not regain power or determine the reason for the power loss. He said he turned the airplane back towards Fort Pierce, Florida, and as it glided towards the airport, he communicated with the air traffic control tower controller, and declared an emergency. As the airplane glided toward the airport the pilot said he became less certain that he would reach it, so he selected a clearing in which to execute a forced landing. Upon reaching 900 feet, he abandoned the approach to the airport and made an approach to a clearing. While on short final to land in the clearing, the right wing of the airplane impacted the top of a pine tree, which changed the path. The airplane pan caked into the ground and bounced into an area of numerous 4-foot high sand piles, coming to rest upright on top of one of the piles. A postcrash examination of the airplane and engine was performed by a FAA licensed mechanic, under the supervision of an FAA inspector. The examination revealed that the magneto had detached from its mounted position, and was hanging by the ignition harness behind the engine. The magneto had not been damage, and the magneto drive gear was laying in the accessory housing along with one "hold-down" plate. The retaining nuts, washers and lock washers were not recovered. When tested, the magneto operated on all eight distributor outputs, and the impulse coupler and the distributor wiring were intact. and undamaged. There was engine continuity as well as valve action and compression on all cylinders. Engine oil was present, and there was evidence that some oil had leaked at the back of the engine. No anomalies were noted to exist with the induction or fuel systems. The airplane and engine had last received an annual inspection in August 2005, when an overhauled engine had been installed. The airplane and engine had accumulated 10 hours since the annual inspection.