Large trees perform best in reducing stormwater flow and pollution. So communities should aspire to grow and sustain large canopy trees even in developed areas. This manual examines and provides cost-efficient options for achieving this goal. Many technical solutions have been developed and are part of this manual. They address both new and retrofit construction and repair techniques to respond to a variety of site-specific requirements such as sidewalk width, public realm condition, and infrastructure arrangement for a range of budgets.