A pilot was performing an aerial survey and required to fly straight and level for four minutes prior to reaching the first survey fix. The pilot was maneuvering the airplane near hills and crossing a ridge while turning to get on course. The pilot looked inside the cockpit to make a power adjustment. Upon regaining his visual, he observed that the airplane would not clear a tall tree directly in front of the airplane’s nose. He turned the airplane to the right to avoid the tree and struck other trees with the right wing. The probable cause was inadequate visual lookout during the turn.A pilot was performing an aerial survey and required to fly straight and level for four minutes prior to reaching the first survey fix. The pilot was maneuvering the airplane near hills and crossing a ridge while turning to get on course. The pilot looked inside the cockpit to make a power adjustment. Upon regaining his visual, he observed that the airplane would not clear a tall tree directly in front of the airplane’s nose. He turned the airplane to the right to avoid the tree and struck other trees with the right wing. The probable cause was inadequate visual lookout during the turn.