JUST AFTER THE ACFT BECAME AIRBORNE FOR A LOCAL SIGHTSEEING FLT, ITS LEFT ENG LOST PWR. THE ACFT YAWED TO THE LEFT & THE LEFT PROP WAS FEATHERED. THE ACFT'S FLT PATH ANGLED TO THE LEFT OF THE RWY & CROSSED OVER TREES TO THE LEFT OF THE DEP END OF THE RWY. DUE TO A LOSS OF SPEED, THE CAPT REALIZED THE ACFT WOULD NOT CLR A 2ND ROW OF TREES, SO HE REDUCED PWR IN THE RGT ENG & MADE A WHEELS UP LNDG IN A CORN FLD. DRG THE LNDG, THE ACFT WAS DMGD. THE LEFT ENG WAS CHECKED AFTER THE ACDNT & IT PRODUCED TAKEOFF PWR. PERFORMANCE CHARTS SHOWED THAT A TAKEOFF DISTANCE OF 3551' WOULD HAVE BEEN REQUIRED TO CLEAR A 50' OBSTACLE. THIS DISTANCE WAS PREDICATED ON A HARD SURFACE; NO CORRECTION FACTOR WAS SUPPLIED FOR A TURF RWY. THE GRASS RWY WAS 3600' LONG. RPRTDLY, THE TAKEOFF WAS STARTED WITH 3500' OF RUNWAY REMAINING. THE PLTS WERE USING THE REAR TANKS FOR TAKEOFF. ACCORDING TO THE FLT MANUAL, TAKEOFFS & CLIMBS SHOULD HAVE BEEN MADE USING THE LEFT & RGT FRONT CENTER WING TANKS, RESPECTIVELY. THE FRONT TANKS HAD ONLY ABOUT 5 GAL OF FUEL REMAINING.