This guide is divided into the following four sections: Section 1. Urban Stormwater Runoff defines urban stormwater runoff and explains why it is a problem. Section 2. The Role of Trees in Stormwater Management discusses what trees need to grow in urban environments and how they help manage stormwater. Section 3. Stormwater Management Systems with Trees provides an introduction to engineered systems available that utilize trees to manage a volume of stormwater. Section 4. Case Studies presents projects from throughout the country that have successfully used trees in the engineered systems discussed. This guide is intended to help engineers, planners, developers, architects, arborists, and public officials understand how trees perform and interact in a stormwater management system, and the new technologies that are being used to increase the stormwater utility function of the urban forest, even in the densest urban environments.