The 1,164-hour commercial pilot reported that he departed the airport on a night VFR cross-country flight to an aerial application airstrip where he was employed to perform aircraft maintenance services. Soon after breaking ground, the tailwheel-equipped airplane entered instrument meteorological conditions and the non-instrument-rated pilot initiated a descent out of the fog with the intention to return to the airport. The airplane impacted trees and terrain while maneuvering to regain visual contact with the ground. The pilot sustained only minor injuries; however, a post-crash fire destroyed the airplane. In a written statement, the pilot stated that he departed while it was still dark, and only gained a little altitude before "encountering IMC conditions." The pilot further reported that he was attempting to lower his altitude and turn back, when the airplane impacted the trees. The pilot reported that there were no mechanical problems with the airplane prior to the impact. In the safety recommendation block of the Pilot/Operator Aircraft Accident Report, the pilot added that since there was no weather reporting stations in the immediate area, it would be "advised to fly only during daytime or on a completely clear night."