Abstract: At approximately 10:00 a.m. on December 12, 2019, a crew of three employees of Zuniga Tree Services were in the process of trimming a pine tree and removing another at a single family residence located in La Mesa, California. Employee #1, a tree climber, was in the tree cutting branches with a portable STIHL® chainsaw. The portable chainsaw kicked-back and lacerated his left forearm. Employees at the scene immediately provided first aid and transported the employee to Urgent Care. The employee then was referred to Palomar Health in Escondido, where he was hospitalized for treatment and observation. There were no accident-related violations issued as a result of the serious injury accident. Zuniga Tree Service, Inc. is a landscaping company that specializes in tree trimming and removal.