The pilot reported that he performed a straight in landing to a private airstrip. He anticipated a crosswind from the east, so he made the approach with additional airspeed to have more controllability in the crosswind. He stated that he landed about two thirds of the way down the 2,574 ft runway, reduced power, and reduced the propeller pitch to low. The tailwheel settled to the ground at a location on the runway where there was a break in the adjacent tree line. The pilot reported that the crosswind intensified at this point, and the airplane yawed to the left. The left main landing gear exited the paved portion of the runway. The pilot attempted to correct with rudder and brakes; however, the airplane continued off the runway and into a plowed field. The airplane nosed over and came to rest inverted in the field. The vertical stabilizer was substantially damaged. The pilot reported that there were no mechanical failures or malfunctions with the airplane that would have precluded normal operation. At the time of the accident, wind at an airport 12 nm northwest of the accident site was 090° at 8 knots. The pilot was landing to the south.