On February 3, 1999, about 1515 eastern standard time, a Bellanca 7KCAB, N68573, registered to Crystal Aero Group, Inc., ran off the runway and collided with trees and terrain during takeoff at Crystal River Airport, Crystal River, Florida, while on a Title 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft received substantial damage and the commercial-rated pilot and one passenger were not injured. The flight was originating at the time of the accident. The pilot stated that during takeoff the aircraft accelerated, the tail lifted off, and the aircraft became airborne. The aircraft then veered to the left and he was unable to correct the departure from runway heading. He maintained engine power and the aircraft appeared to be gaining height, but was still turning to the left. The wings remained level and there was no buffet. The aircraft then struck the higher part of some small trees and he closed the engine throttle. The aircraft came to rest, nose down, in about 2 feet of water. Postcrash examination of the aircraft was performed by an FAA Inspector. The engine rotated and continuity of the engine assembly was confirmed. The propeller had damage consistent with rotation at low power at the time of ground impact. The engine fuel system was clear of debris and contamination and 100LL fuel was found in the system. All flight controls operated normal. The inspector stated he reviewed a photo taken shortly after the accident and it showed a branch had lodged in the elevator forcing the elevator to the full down or aircraft nose down position. (See attached inspector statement)