The pilot of the experimental, amateur-built, biplane reported that, following a normal initial climb, about 100 ft. above the ground, the biplane started an un-commanded turn to the left, followed by a descent. He added that, it became apparent that the flight path was into the tree line, and he "attempted to climb to possibly maintain at least an altitude to clear the trees, but to no avail, nearly stalling." Subsequently, the biplane impacted the trees. The biplane sustained substantial damage to the wings and fuselage. The pilot reported that there were no preaccident mechanical failures or malfunctions with the biplane that would have precluded normal operation. The pilot added that, the biplane is "not very stable once in a flying configuration, any air mass (gusts) change can disturb the balance and result in self-induced turns, climbs and descents. These movements have to be countered immediately because of the relative size (small) of control surfaces (rudder, ailerons). And corrections are slow, possibly resulting in loss of altitude. Pilots expect these upsets and become alert for them." The automated weather observation system on the accident airport reported, about the time of the accident, the wind was 360° at 5 knots. The pilot was departing on runway 03. The calculated density altitude was 1,897 ft.