The pilot and passenger were conducting an aerial observation flight at low altitude to inspect power lines. The pilot stated he maneuvered to do a right turn and encountered a gust of wind. The pilot lost tail rotor effectiveness and attempted to recover control of the helicopter. Before the pilot could regain full control, the helicopter descended into the tree tops and came to rest in a tree. The helicopter sustained substantial damage to the tail boom. The pilot reported no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation.