The commercial pilot was landing the airplane at an off-airport site that required an approach over trees. During the final approach phase of the landing, the left wing struck a previously unnoticed tree branch, and the airplane veered to the left of the intended touchdown point. The pilot attempted to correct to the right, but the airplane touched down to the left of the landing site and collided with trees. The airplane sustained substantial damage to both wings, fuselage, and empennage. The pilot reported that there were no preaccident mechanical anomalies with the airplane.