Landscape
Chapter 26 of the New Urbanism Best Practices Guide
Abstract: Based on satellite images, American Forests has reported a decline in the tree canopy in many US cities. As tree cover declines, the urban “heat island” effect intensifies, and cities lose other benefits, such as absorption of carbon dioxide, removal of pollutants from the air, reduction of human stress, increase in property values, and definition of street spaces, This chapter looks at difficulties that trees encounter in the urban environment, such as poor soil, compaction, inadequate drainage, utility trenches, undersized tree grates, and excessive paving. The text then explains recommended practices, such as installing trenches with a “structural soil volume” allowing roots to grow beneath sidewalks.
James Urban of Urban Trees and Soils presents 10 strategies of three different kinds (soil-based, tree-based, and management-based) for cultivation of trees in cities. An excerpt and illustrations from the Verano [Texas] Community Design Book provide recommendations governing continuous tree planting, planting in grates, medians, and promenades, and planting along park drives. Duany Plater-Zyberk & Company presents a Transect-based approach, including a table from the SmartCode showing six common types of tree shapes and their appropriateness in various settings.
Agricultural urbanism — the integration of farms and gardens of varying scales into a community — is explored through the 538-acre Southlands tract British Columbia. Organized along the Transect, the residential and food- and plant-growing activities at Southlands are envisioned as ranging from high-density housing with window boxes, to somewhat less dense houses with kitchen gardens, to quarter-acre plots, 50-acre farms, and a 160-acre farm. Market Square is a key public space where the town meets the agricultural edge. The chapter concludes with an organic farm at New Town at St. Charles in Missouri, intended to be an amenity for residents but also a food source and a viable business.
