On July 29, 2013, about 0810 central daylight time, an Eagle DW-1, N8803Z, struck trees while engaged in aerial application southeast of Eagle Lake, Minnesota. The pilot, the sole occupant on board, was not injured. The airplane was substantially damaged. The airplane was registered to a private individual in Arizona, and operated by ASI Jet Ag, Eden Prairie, Minnesota, under the provisions of 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed for the flight, and no flight plan had been filed. The flight originated from Waseca (ACQ), Minnesota, about 0750.According to the pilot's accident report, he pulled up (as he had on previous passes) to avoid a treeline on the south edge of the field. He noticed he was getting too close to the tallest tree and he applied full power and pulled maximum elevator deflection. The airplane clipped the top of the tree with its right wing and yawed to the right. He proceeded to Mankato and landed without incident. The pilot told a Federal Aviation Administration (FAA) inspector that he had just finished the fourth pass over a field. As he pulled up, he misjudged the height of nearby trees and struck the top of one of the trees. The pilot was able to fly the airplane to nearby Mankato (MKT), Minnesota, and land without further incident. Postaccident examination revealed forward and aft spar damage to the right wing. The pilot reported no mechanical issues with the airplane.