A man who had been trimming trees in Oconee County was found dead Monday afternoon, hanging from a rope 70 feet in the air, according to Oconee County Emergency Services Deputy Chief Adam Williams.Coroner Karl Addis said David Wayne Vaughn, 57, of Walhalla, was found suspended by his safety harness and rope.  Addis said Vaughn had no obvious fatal injuries, although his being struck by a falling branch has not yet been ruled out.  It is possible he had a fatal medical event while in the tree, Addis said. Vaughn was self-employed as an arborist and had been working on the property on Holly Lane in Walhalla since about 8 a.m. He had topped and trimmed the upper branches of the tree before his death, Addis said.The homeowners went outside after not hearing sawing for a while, and found Vaughn unconscious up in the trees, Williams said.Williams said the Pickett Post-Camp Oak Fire Deparment was called just after 1 p.m. The fire department requested a ladder truck from the Keowee Fire Department and assistance from the Oconee County Special Rescue Team.Rescuers found they could not reach Vaughn via the ladder truck, so they set up a high-angle rope system.  Once a rescuer reached Vaughn, it was determined he had died.Williams said Vaughn was lowered to the ground in what he described as a very risky operation that took about 30 minutes.Addis said an autopsy will be performed to determine the cause of Vaughn’s death.