Defective trees are potential hazards to people and property in recreation areas. Most reported tree failures within recreation sites in the Rocky Mountain Region occur in lodgepole pine. Defective root systems account for the greatest percentage of failures. External indicators of defects are used to identify trees that may fail. Some tree species, particularly aspen, are highly susceptible to visitor damage; managers should restrict recreational development in such forest types. Old growth spruce-fir stands should also be avoided for developed sites. Systematic, annual, documented inspections of trees in recreation sites and corrective action are recommended to reduce hazards to the public.

This brochure was created to help home owners and land managers recognize hazardous defects in trees and to suggest possible corrective actions. Audience: This would be a valuable resource for landscape architects, homeowners, property managers, municipal and state tree wardens, and others who are involved in the preservation of trees. Other related products: National Individual Tree Species Atlas can be found here:https://bookstore.gpo.gov/products/sku/001-001-00703-0 Container Tree Nursery Manual, V. 7: Seedling Processing, Storage, and Outplanting --print format can be found here:https://bookstore.gpo.gov/products/sku/001-001-00689-1 --ePub format can be found here: https://bookstore.gpo.gov/products/sku/999-000-33334-1 Trees & Forests resources collection is available here:https://bookstore.gpo.gov/catalog/environment-nature/trees-forests

Trees add to our enjoyment of outdoor experiences whether they're growing in forests, parks, or urban landscapes. Too often, we are unaware of the risks associated with defective trees, which can injure people and damage property. There has been more interest in tree risk management in recent years because of safety and liability concerns that result from preventable accidents. Recognizing hazardous trees and taking proper corrective actions can protect property and save lives. A tree is considered hazardous when it has "structural defects likely to cause failure of all or part of the tree, which could strike a 'target' and cause an unacceptable degree of injury or damage." A target can be a vehicle, building, or a place where people gather such as a park bench, picnic table, street, or backyard.