This publication is a guide for protecting, conserving, selecting, maintaining, removing, and replacing trees on development sites in the Pacific Northwest. The guidebook is designed to assist people who work with trees during the development and construction phases of both new and existing projects to keep healthy trees a part of the urban environment through the use of accepted tree care standards and practices. This publication provides best management practices (BMPs) developed and recommended by professional arborists, urban and community foresters, and landscape architects. BMPs are widely accepted practices and standards used by industry professionals and based on the best available research. The guidebook provides basic and practical information about methods to give trees planted or retained on development sites the best chance to survive and thrive during and after the construction process.