The pilot arrived in the area of his destination about sunset but was unable to locate the station airstrip. After a short search he found another strip with some buildings nearby and decided to land to ascertain his location. An aerial inspection of the strip was completed. However, the pilot reports that when the aircraft was on final approach he noticed that what he had assumed was low scrub near the threshold was in fact 10 metres high trees. He adjusted the approach and touched down further down the strip than had been planned. The strip surface was loose and maximum braking could not be applied. The aircraft overran the strip and collided with rocks and a dirt bank which resulted in the left main and nose landing gear legs collapsing. The strip was approximately 800 metres in length.