Abstract: At approximately 10:30 a.m. on May 25, 2011, an employee and a coworker were performing tree maintenance work on a tree at northeast end of the property and adjacent to a 7 foot sound wall that bordered a residence. The employee arrived at the site in a heavy GM C70 model truck, equipped with a 50 foot articulating boom and personnel hoist. He was in a personnel bucket that was positioned to access and trim branches in an oak tree that required trimming. In an attempt to access branches beyond their reach while in the bucket, the employee exited the bucket, and ascended into the tree using a rope thrown over a large limb and then tied one end of the rope to his body belt, before pulling himself up and onto a limb approximately 5 to 6 feet above the sound wall below. The employee cut several branches, and was descending back into the bucket, when he fell approximately 13 feet below, several feet from the wall, onto the ground and in the backyard of the residence. Shortly after the accident, a lead worker contacted a main office, and they in turn called for Emergency Medical Services. The San Ramon Valley Fire Department arrived, treated, and then transported the employee to John Muir Hospital in Walnut Creek. The employee was admitted at John Muir Hospital for emergency treatment of a shattered pelvis, fractured vertebrae in the neck, fractured ribs, and head contusion, and was eventually released for out-patient care on May 30, 2011.