The pilot was departing, uphill, from a remote off-airport site. The rough and gravel-covered site was about 600 feet long, with soft vegetation, and 25-30 foot tall trees approximately 150 feet beyond the departure end. The wind was variable with moderate gusts. When the pilot realized that he did not have enough airspeed or remaining runway to clear the obstacles at the departure end of the site, he aborted the takeoff. The airplane subsequently overran the southeast end of the site, into an area of tree-covered, rough and uneven terrain, sustaining substantial damage to the fuselage, wings, and empennage. The pilot reported that there were no mechanical problems with the airplane prior to the accident.