Sidewalk street trees are an essential part of a Grand Boulevard vision for the corridor. In addition to beautification, benefits include pavement shading, greenhouse reduction, and, in combination with Low Impact Development elements, absorption of stormwater runoff.
Sidewalk street trees should be planted along all frontage sidewalks given sidewalk space and roadway visibility constraints. To promote a boulevard appearance and maximize environmental benefits, trees should be regularly spaced, with species characteristics including a high-branching, broad spreading canopy; a more columnar form may be appropriate in locations with narrow clearances. High-branching trees are recommended for visibility as well as street light and truck/bus clearance.
Deciduous species are strongly recommended to provide sun in winter months. Trees must be located a minimum 18 inches from face of curb per State highway design standards. However, a minimum tree well width of 4 feet and minimum setback of 2 feet 6 inches from face of curb is recommended. The location of street trees and streetlights should be coordinated to minimize conflicts.
Figure 5-16 depicts sidewalk street trees located at approximately 50 feet on center, with 6-foot square tree wells and a continuous pervious paving and subsurface structural soil trench located within the amenity zone area. Streetlights are depicted mid-way between the street trees. Figure 5-16 illustrates clearance and visibility considerations for sidewalk street trees.