The Black Sheep Aviation and Cattle Company DHC-3T Turbine Otter had been loaded with a cargo of lumber at Mayo, Yukon. The aircraft was taxied to the threshold of runway 06 and the pilot began the take-off roll. At lift-off, the aircraft entered an extreme nose-up attitude and began to rotate to the right. Shortly thereafter, the aircraft struck the airport ramp. The pilot, who was the sole occupant of the aircraft, was fatally injured. A small post-impact fire was extinguished by first responders. It appeared the aircraft was loaded in a manner that resulted in the CG being aft of the rearward limit. The smooth surface of the finished lumber provided less friction against the plywood cabin floor. The cargo was only secured with one lateral strap and it is likely that the shorter finished boards moved aft during the taxi and take-off roll, which would result in a significant rearward shift of the CG. The rearward shift of the CG during the taxi and take-off roll resulted in C-GZCW pitching nose up, stalling and entering an incipient spin from which the pilot was not able to recover. Findings as to Causes and Contributing Factors: 1. The aircraft was loaded in a manner that resulted in the centre of gravity being aft of the rearward limit. 2. Because the cargo was not properly secured, it shifted towards the rear of the aircraft, resulting in the centre of gravity moving further aft, causing the aircraft to pitch up and stall.