The commercial certificated pilot, a Fish and Wildlife Protection Officer, was landing on the beach area of a lake, adjacent to a remote lodge. The pilot and passenger were concluding a cross-country public use flight to conduct a criminal investigation. During the landing roll, the right wingtip contacted willow bushes, pivoting the airplane to the right. The airplane received damage to the propeller, the tailwheel assembly, the rudder post, and a fuselage longeron.