THE PLT WAS CLEARED TO EXECUTE A VISUAL APPROACH TO RWY 21 AND WAS ISSUED THE CURRENT ALT SETTING OF 29.60' HG. THE APPROACH WAS MADE UNDER DARK NIGHT AND GUSTY CROSSWIND CONDITIONS TO A LIGHTED RUNWAY IN RURAL MOUNTAINOUS/HILLY TERRAIN. DURING FINAL APPROACH THE ACFT COLLIDED WITH A TREE LOCATED APPROX 3,500' FROM RWY 21 AT APPROX 1,300' MSL. THE APRT ELEVATION WAS 1,203' MSL. THE AIRCRAFT CAME TO REST AT APPROX 1,280' MSL ON A HILLSIDE. A PHOTO WAS TAKEN BY RESCUE WORKERS THAT SHOWS THE ALT INDICATING 1,430' MSL. THE ALT SETTING FOUND IN THE WRECKAGE WAS 29.74' HG. THE PLT COULD NOT RECALL SETTING THE ALT PRIOR TO THE APPROACH. THE ALT WAS TESTED AND FOUND TO OPERATE PROPERLY. THE PLT REPORTED THAT NO PRE-IMPACT DEFICIENCIES WERE PRESENT IN THE ACFT AND COULD NOT RECALL THE ACCIDENT. WINDS WERE RECORDED AS GUSTING TO 18 KNOTS AND WHEN THE TOWER CLEARED THE ACFT TO LAND THE CONTROLLER STATED THAT THEY WERE GUSTING TO 16 KNOTS.