THE PILOT OF A SKI EQUIPPED AIRCRAFT BEGAN TAKING OFF ON A 900 FT STRIP. THERE WAS SNOW ON THE RUNWAY, BUT GRASS SHOWED THROUGH IN PLACES. THE PILOT REPORTED THAT THE AIRCRAFT SLOWED "VERY VERY LITTLE" WHILE CROSSING AN AREA WITH GRASS SHOWING. JUST BEYOND THIS SPOT, THE AIRCRAFT ENCOUNTERED AN AREA OF DEEPER SNOW WITH NO TRACKS PREVIOUSLY BROKEN THROUGH. THE PILOT REPORTED THAT THE AIRCRAFT WOULD NOT ACCELERATE IN THE DEEPER SNOW. THE LAST 40 TO 50 FT OF THE FIELD SLOPED DOWNWARD TO THE REMAINS OF A STONE WALL THAT HAD BEEN PARTIALLY REMOVED. JUST BEFORE GOING OFF THE SLOPE, THE PILOT ROTATED AND THE TAILWHEEL DRAGGED THROUGH THE DEEP SNOW. THE AIRCRAFT BECAME AIRBORNE, BUT SETTLED. THE TAIL OF THE PLANE STRUCK THE STONE WALL AND THE EMPENNAGE SEPARATED. THE AIRCRAFT CONTINUED THROUGH SOME BUSHES AND A SWAMPY AREA BEFORE COMING TO REST.