On July 17, 2013, about 1625 eastern daylight time, a Grumman Aircraft Cor-Scweizer G-164A, N8719H, impacted trees and terrain during an aerial application of an agricultural field. The airplane was consumed by a post impact fire and sustained substantial damage. The pilot sustained serious injuries. The airplane was registered to and operated by SLF Air LLC under 14 Code of Federal Regulations Part 137 as an aerial application flight and was not operating on a flight plan. The local flight originated from Gaylord Regional Airport, Gaylord, Michigan, about 1555. The airplane was loaded with about 200 gallons of chemical, of which about 100 gallons had been sprayed. The pilot sprayed a field in an easterly direction and towards a tree line, which was about 60 feet in height, when the airplane impacted the trees. The wreckage path through the tree was about 150 feet. The airplane came to rest inverted and facing toward the west. A post impact fire burned an area of about 100 feet around the main wreckage. The propeller blades were "curved." On-scene examination of the airplane by the Federal Aviation Administration revealed no mechanical anomalies. A National Transportation Safety Board Pilot/Operator Aircraft Accident/Incident Report was not received from the pilot.