Half a Million Trees: Prototyping Sites and Systems for Sustainable Cities

IntroductionThis studio addresses design and planning practices of sustainable urban forestry. The decline of our urban forest cover can be addressed as a series of fundamental design problems: how we grow trees, how we place them in the ground, how long we expect them to thrive, how we use the space where they grow, and how we manage these decisions as a sustainable, common cultural asset. With the help of experts in production growing, soils building, arboriculture, urban social programming, and governance, the studio plans to confront these questions with the goal of devising new strategies and applying them to myriad urban conditions in South Boston. Through research and design, we expect to unearth a new engagement of urban structure that considers how we plant at all scales. The research outcomes and design proposals proposals are intended to be published as the foundation for a multi-year project on sustainable planting practices.BackgroundChicago Mayor Richard Daley\’s administration has planted half a million trees since 1989. Mayor Michael Bloomberg has pledged one million for New York by 2030, and Boston Mayor Thomas Menino plans to increase his city\’s canopy cover by 20% by 2020. U.S. Mayors in cities across the country are recognizing the stark decline in urban tree cover over the past 30 years. They are prioritizing canopy restoration in response to the climatic and socio-economic challenges of the contemporary American city. But planting more trees without considering the requirements for longevity in the current urban territory is not enough.Livable cities, in temperate zones of the eastern United States and elsewhere, require an extensive, sustainably managed urban tree cover. People need shade, and mature canopies enhance both spatial qualities and real estate values of neighborhoods and streets. Even as purely visual amenity, the urban canopy has calculable (and compelling) value. For example, Toronto\’s urban forest, evaluated \”on an average value of $700 per tree set by the Council of Tree and Landscape Appraisers in 1992, is [worth] over $16 billion\” (\’Evolving Urban Forest Concepts and Policies in Canada\’ by Ken Farr).But the urban tree canopy has another quantifiable value as green infrastructure as essential to the successful functioning of the city as sewer pipes or water lines. As a continuous dynamic system, the urban canopy reduces stormwater flows, cleans runoff, protects groundwater, reduces energy costs, increases the health and productivity of soil, slows erosion, supports carbon sequestration, and provides critical urban habitat. Though the visual/spatial value of urban trees is accepted in many communities (as the infrastructural one is becoming so), on the whole, cities regularly fail to plant sustainably. A constant threat to the urban canopy prevails, whether by successive catastrophic events or slow decline. In their study of urban canopy loss in D.C. metro area, the non-profit organization American Forests has established that in the years between 1973 and 1997, there was a 64% loss in acres of land with heavy tree cover (50% or more). This translates to an increase of millions of dollars in associated stormwater and air pollution control costs.Without taking sides in the current debate about trees and climate change, the studio will examine innovative growing practices in the nursery industry and urban forestry, along with emerging practices in urban soils science, and stormwater management and apply these to several scales of urban design. Whether through planning or through adaptive, organic growth, urban tree reservations–located on streets and parkways, waterways, parks, vacant lands, and throughout private backyards – can be newly conceived to promote a truly sustainable urban forest – as both green infrastructure and civic legacy.The studio will research the primary functional attributes of urban t