Hear from a certified arborist. The Debris Management Task Force prioritizes safety and tree health when assessing hazard trees. To manage this balance, arborists working with our task force crews are certified. Think of an arborist as a tree surgeon who is a professional both educated and experienced in the practice of arboriculture, which is the study of individual trees, shrubs, vines, and other perennial woody plants in dendrology and horticulture.