The certificated airline transport pilot was attempting a southwesterly departure from a 750 feet long dry creek bed. He stated that during the takeoff roll, and about 700 feet down the creek bed, he applied 25 degrees of flaps. The airplane became airborne, but failed to gain sufficient altitude to clear rising terrain. The airplane's right wing collided with a stand of trees, pivoting the airplane to the right, and the left wing struck the ground. The airplane's wings, and lower left longeron sustained substantial damage.