16.50.070 Tree conservation standards.
A. Minimum Tree Density—New Uses on Vacant or Redeveloping Lots. This section promotes tree conservation by establishing minimum tree density requirement, expressed as one tree unit per one thousand square feet. It is intended that the tree density requirement will be met primarily through the conservation of existing trees. However, in order to provide for continued flexibility in the design of new development, in those situations where a development’s design would preclude the retention of the required number of trees, the use of replacement or supplemental tree planting is authorized.
B. Sites with Insufficient Tree Cover. It is recognized that some sites may not contain a sufficient number of existing trees to meet the tree density requirement. In those situations, additional trees shall be planted as necessary to achieve the requirements of this chapter, unless off-site mitigation is followed.
C. Off-Site Mitigation. Where an applicant cannot provide sufficient on-site benefits, off-site mitigation, based on the recommendation of the tree commission, may be approved by the city council. Where off-site mitigation is used, the remaining balance of trees must be planted at an off-site location approved by the parks department. Where the site is city-owned property, the public works or parks departments must also approve the tree planting. Acceptable off-site locations, in general order of priority, are as follows:
1. Publicly owned parks or recreational facilities within the city of Anacortes;
2. Publicly owned land in the city of Anacortes including, but not limited to: critical areas, regional stormwater facilities, or wildlife corridors. Similar lands owned by non-profit entities which are reserved in open space also qualify;
3. Public school sites within the city of Anacortes;
4. Street rights-of-way adjacent to city facilities or adjacent to private property when approved by the property owner (street trees);
5. Other mitigation or restoration sites managed by other public entities or private conservation groups;
6. Other sites proposed by the applicant, when it is documented that higher priority sites are not available or viable.
D. Tree Density Requirements.
1. All regulated activity shall ensure that the following tree density shall be achieved and maintained during and after development: one tree unit per one thousand square feet;
2. Calculation of the Total Tree Units Required. The total number of tree units required to be provided by a regulated project or tree conservation permit approval listed in Section 16.50.100 shall be calculated by dividing gross site area, minus any public or private street rights-of-way, by one thousand Table 16.50.120(D). The result of the calculation will be the total number of tree units required for the project approval within the building site.
a. The tree unit calculation shall include retained or newly planted trees within the site as well as newly planted street trees located in contiguous public rights-of-way or alleys.
3. Tree Unit Credits. The number of tree unit credits given for retaining existing trees or the planting of new trees varies with tree size in order to encourage the retention of large existing trees and the planting of replacement trees that provide greater canopy areas at maturity. Tree unit credits for the retention of existing trees and the planting of new trees shall be assigned as follows:
|
Tree Size Category |
Tree Unit Credits |
|---|---|
|
Existing tree 2" to 5" d.b.h. |
1 tree unit per tree retained and protected |
|
Existing tree 5.1" to 10" d.b.h. |
2 tree units per tree retained and protected |
|
Existing tree 10.1" to 25" d.b.h. |
5 tree units per tree retained and protected |
|
Existing tree 25.1" d.b.h or larger |
8 tree units per tree retained and protected |
|
New or replacement tree |
1 tree unit per tree planted See Section 16.50.080(B) |
*See diagrams for definition of multi-trunk tree on Page 3, Figure 1.
(Ord. 2756 Att. F, 2006)