The pilot reported that following a brief local flight, he returned to the departure airport and entered the traffic pattern. While on final approach to the runway, he initiated a slip to the left in order to descend and increase the visibility of the runway. The pilot stated that during previous flights in the tailwheel-equipped biplane, after exiting the slip just prior to touchdown, the airplane's airspeed would increase, and it would "float" down the runway; however, upon exiting the slip during the accident flight the rate of descent remained constant, and the airplane's contact with the runway was "fairly severe." The landing gear subsequently collapsed, and the airplane departed the right side of the runway and nosed over, resulting in substantial damage to the right upper wing. The pilot reported that there were no mechanical malfunctions or failures of the airplane that would have precluded normal operation, and that the accident could have been prevented by a "quicker reaction" and "increasing [engine] power to arrest descent rate."