The pilot was on a personal scenic tour flight; the airplane was climbing southwest, and approaching 9,000 feet mean sea level. He planned to cross a mountain saddle between 400 and 500 feet above ground level. The flight encountered a strong downdraft; the airspeed dropped to about 80 mph,and the airplane stopped climbing. It then encountered another downdraft, which resulted in the airplane descending. The pilot attempted to arrest the descent by applying full engine power, but was unsuccessful. He maneuvered the airplane to avoid some trees before impacting the rising terrain. The airplane sustained substantial damage to both wings and the tail section. The pilot reported no preimpact mechanical malfunctions or failures with the airplane that would have precluded normal operations.