PURPOSE

  1. To create shaded streets as a way to increase property values, slow vehicular traffic, and reduce heat effects to people walking and living nearby.

APPLICABILITY

  1. Street tree standards apply to any project that creates or modifies a thoroughfare and any development that fronts a thoroughfare.

GENERAL

  1. The required shape of street trees must be determined by the District as indicated in the Tree Plantings by District table.
  2. The [PERMITTING AUTHORITY] may exempt applicants from the street tree requirement when:
    1. The minimum number of required street trees already exist in the furnishing zone of the abutting thoroughfare.
    2. One or more mature, healthy trees planted on-site in close proximity to the front lot line, with canopy reaching over the abutting thoroughfare, would cause overcrowding of new street trees.
    3. The specific location of an existing curb cut, utility line, or other feature conflicts with the proper placement of a street tree.
  3. The [PERMITTING AUTHORITY] may require an in-lieu fee or street tree installation in alternative locations when installation cannot be accommodated within the furnishing zone of the abutting thoroughfare.
  4. Sidewalks must include large trees planted within the furnishing zone, except for alley sidewalks.
  5. Trees must be planted in a regularly-spaced allee pattern between thirty-five (35) and forty-five (45) feet on center, as required depending on species or cultivar of tree.
    1. Along retail frontages, street trees may be planted in an irregularly-spaced allee pattern to avoid visually obscuring storefront windows and signage.
    2. The review boards may grant a waiver from the street tree requirements of this section only for sidewalks in front of terminated vistas and abutting civic spaces.
  6. At least one thousand (1,000) gross cubic feet of soil volume space must be provided for each tree within a maximum twenty-seven (27) foot radius of the tree trunk.
    1. Where required soil volumes for nearby trees overlap, up to twenty-five percent (25%) of the required soil volume per tree may be shared between trees.
    2. Soil volume under paved surfaces must be provided through suspended pavements or structural cells. A sand-based structural soil system may be used with approval of the [PERMITTING AUTHORITY].
  7. When planted, trees must be a minimum height of ten (10) feet or two (2) inches in caliper.
  8. Tree pits must have an open soil area centered at the tree trunk that is at least thirty six (36) square feet (such as 6’x6’).
  9. To reduce soil compaction, shield a tree’s trunk from physical damage, and prevent pet waste from entering the soil area, a tree guard at least eighteen (18) inches tall must be installed around the outer perimeter of the tree pit.
    1. For sidewalks without an edge zone (i.e. ‘Curbwalk’), tree guards must be three-sided and positioned at least one foot short of the outer edge of the curb, with the curbside remaining open (not fenced).
    2. For sidewalks with an edge zone, tree guards must provide protection on all four sides of the tree pit.
    3. Tree guards must allow for water to flow from the sidewalk into the tree pit.
  10. Coarse grade groundcover mulch must be applied to the soil area at a depth of at least two (2) inches and distributed to create a smooth, level cover over the exposed soil at the time of planting.
    1. A gap of approximately eight (8) inches must be left between the mulch and the trunk of the tree to avoid mounding above the trunk flare.
  11. Trench drains located between the curb and furnishing zone or between the furnishing zone and walkway are recommended to maximize water infiltration into the soil provided for street trees
  12. When tree pits are required, they must consist of a rectangle, no smaller than 36 sf in size, with a minimum width of 48 inches, and be spaced along the length of a thoroughfare by at least 35 feet.
  13. Thoroughfares with a right-of-way of less than 40 ft, or a verge less than 9 ft, are not required to provide street trees.
  14. Columnar and ornamental varieties of trees may not be used as street trees except by special permit.

TREE PLANTINGS BY DISTRICT