Abstract: At 11:26 a.m. on February 6, 2020, an employee and three coworkers were pruning two madrone trees next to a building at a remote site. Two coworkers were climbers that were each in one of the two trees using chain saws to trim branches. The employee was removing the branches from below the trees while another coworker was operating a chipper machine. The employee was walking under the tree pulling a winch line from the chipper machine to a branch to be pulled to the chipper. A coworker in the tree looked to see that the employee was not below him in the drop zone then started making cuts in a branch but never looked again to see if the drop zone remained clear before making the final cut and dropping the branch. The tree branch was approximately 8 inches in diameter and 20 feet in length. The branch fell approximately 40 feet and struck the employee who had walked into the drop zone. The crew was using verbal communications with each other during the tree trimming operations including the grounds men yelling up to the climber in the tree before entering the drop zone and the climber in the tree yelling "headache" before cutting and dropping a branch. The employee did not yell "headache" before finishing the final cut and dropping the branch. The drop zones were not discussed before the trimming operations began as the crew believed it was a "common knowledge" thing that the area below the employee in the tree is the drop zone. A drop zone could be under one side of the tree below a climber making cuts and not under the other side of the tree. The drop zone would move as the climber in the tree moved about the tree. The grounds men were responsible for looking for the location of the employees in the trees to determine the location of the drop zones. The employee suffered serious injuries, requiring hospitalization for treatment.