The airplane impacted trees and terrain during a forced landing following a loss of engine power at 1310 Pacific time. The Private pilot and passenger sustained minor injuries; the airplane was destroyed. Visual conditions prevailed. According to the pilot, the flight was about 35 miles out from its destination when he initiated a descent by reducing power. About four miles from the airport at 4000 feet, engine rpm and manifold pressure began to steadily decrease. The engine did not regain power, and the pilot diverted his attention to an emergency landing spot. During the forced landing the left wingtip clipped a tree limb and the airplane impacted the ground. The pilot had purchased the airplane the day before and flown it from Kansas to California. The Lycoming IO-320 engine had been rebuilt about 95 hours prior to the accident after a propeller strike.