The pilot reported he landed to the southeast on the 3,700 foot long grass/gravel airstrip and then taxied back to the northwest end of the runway to takeoff. The field elevation of the airport is 7,554 feet. The pilot set the brakes and advanced the engine power to perform a soft/short field takeoff. The airplane lifted off at about 60 – 62 miles per hour and the pilot kept the airplane in ground effect to gain airspeed. The pilot reported the runway sloped down 20 to 25 feet at a point about 1,200 prior to the departure end of the runway. Upon reaching the downslope, the airplane lost lift as if it encountered a downdraft. The pilot reported he overcorrected and the airplane stalled. The left wing contacted the runway, followed by the landing gear and the right wing. The nose gear collapsed which resulted in the airplane coming to a stop. The pilot was able to exit the airplane before it was destroyed by a postimpact fire. The pilot reported there was no mechanical failure or malfunction of the airplane which would have preclude normal operation.