Chapter 18.180
TREE RETENTION

Sections:

18.180.010    Purpose.

18.180.020    Applicability.

18.180.030    Retention required.

18.180.040    Alternative tree retention option.

18.180.050    Reduced landscaped areas.

18.180.060    Tree retention plan.

18.180.070    Tree protection measures.

18.180.080    Long-term tree protection and maintenance.

18.180.010 Purpose.

The purpose of this chapter is to retain trees in the city in order to preserve and retain clusters of existing trees that contribute to the city’s community character; maintain and protect property values; enhance the visual appearance of the city; reduce the impacts of development on the storm drainage system and water resources; and provide a better transition between the various land uses permitted in the city. (Ord. 2013-04 § 2 (Exh. A (part)), 2013)

18.180.020 Applicability.

Retention of trees shall be evaluated during the following:

A.    New development projects in the RL zoning district, including subdivisions, planned residential developments, and nonresidential uses.

B.    New development projects in the RM/RH zoning districts, including multifamily developments; live/work and mixed use; assisted living, congregate care facilities and the like; and nonresidential uses.

C.    New development projects in the C-3 zoning district that are located east of Tenth Avenue, from Lincoln Avenue to Forest Rock Lane.

D.    New projects utilizing master plan overlay provisions. (Ord. 2013-04 § 2 (Exh. A (part)), 2013)

18.180.030 Retention required.

A.    In applying the requirement for retention of trees, the review authority shall consider the preservation of trees in any of the following circumstances as priorities:

1.    Trees located within healthy, vegetated groups and stands, rather than as isolated trees scattered throughout the site.

2.    Trees that have a reasonable chance of survival once the site is developed.

3.    Trees that can be incorporated into required landscaping and setback areas.

4.    Trees adjacent to required critical area buffers.

5.    Trees having a land stability function.

6.    Trees that can be incorporated into a perimeter buffer or screen the site from adjacent properties.

7.    Trees that can be incorporated into required open space and/or recreational amenity areas or tracts.

8.    Trees that will not pose a threat to persons or properties.

9.    Conifers which provide for superior ability to intercept stormwater during high rain events over deciduous trees.

B.    Tree Retention Requirement.

1.    At least twenty-five percent of the existing trees which are ten inches in diameter or greater measured four feet six inches above grade, and meet the priorities in subsection A of this section, shall be retained.

2.    The review authority may approve retention of trees which do not meet the size requirement above as a contribution toward the sum of the diameter inches required if a group of trees and its associated undergrowth can be preserved and falls within one of the priorities identified in subsection A of this section. (Ord. 2016-20 § 2 (Att. A (part)), 2016; Ord. 2013-04 § 2 (Exh. A (part)), 2013)

18.180.040 Alternative tree retention option.

The review authority may approve an alternative tree retention option, when the alternative is one of the following alternatives:

A.    Incorporates the replacement of trees equal in equivalent diameter inches as required in Section 18.180.030(B).

B.    Incorporates the retention of other trees and natural vegetation in equivalent diameter inches as required in Section 18.180.030(B) and is in consolidated locations that promote the natural vegetated character of the site.

C.    Where an alternative proposal includes supplemental or replacement trees in lieu of retention, the applicant shall utilize plant materials which complement the natural character of the Pacific Northwest, and which are adaptable to the climatic, topographic, and hydrologic characteristics of the site. A landscape plan is required to be submitted.

D.    Where an alternative proposal includes supplemental or replacement trees in lieu of retention, the application shall be required to provide a maintenance assurance device, as set forth in Section 18.130.060(C) or (D). (Ord. 2013-04 § 2 (Exh. A (part)), 2013)

18.180.050 Reduced landscaped areas.

If a project includes the retention of trees or alternative option above that is required by this chapter, the review authority may approve a reduction of the project’s landscaping requirement by the equal amount of square footage the additional tree retention has added; provided, that a project’s yard setback landscaping requirement remains unaltered. (Ord. 2013-04 § 2 (Exh. A (part)), 2013)

18.180.060 Tree retention plan.

A tree retention plan or alternative tree retention option shall be prepared and submitted with the associated land use permit for projects identified in Section 18.180.020.

A.    Trees designated for retention shall be shown on the project site plan, plat drawing and/or landscape plan; a project-specific tree retention written narrative shall be included.

1.    The tree retention plan and narrative shall detail how the proposal meets the requirement of this chapter.

2.    Tree tract(s), open space tract(s) or other permanent protective mechanism shall be utilized to specifically identify the areas set aside for tree retention.

B.    The city may request the city arborist to review and provide a recommendation on the project’s proposed tree retention plan. If requested, the review by the city arborist will be at the applicant’s expense. (Ord. 2013-04 § 2 (Exh. A (part)), 2013)

18.180.070 Tree protection measures.

A.    Prior to initiating tree removal and land alteration on the site, trees and vegetated areas identified during land use permit approval to be preserved shall be protected from potentially damaging activities.

1.    Tree retention tract(s), open space tract(s) or other protective mechanism shall be depicted on all submitted construction or land alteration plans, including but not limited to land clearing and grading permits, final landscape plans, and engineering construction drawings.

2.    Tree retention tract(s), open space tract(s), or other protective mechanism shall be shown on the face of the plat, binding site plan or similar documents, with a note on the face describing the purpose for long-term retention.

3.    The retained trees should be drawn to scale, protective measures included in the construction notes, and the detail for protection fencing included.

B.    Before land clearing, filling or any land alteration approved through a land clearing or grading permit, the applicant:

1.    Shall install a visible protective tree fencing along the outer edge and completely surrounding the protected area (dripline/critical root zone) of all protected trees or groups of trees. Fences shall be constructed of chain link or other approved material and at least four feet high, unless other type of fencing is authorized by the review authority.

2.    Shall prohibit excavation or compaction of earth or other potentially damaging activities within the barriers.

3.    Shall maintain the protective barriers in place until the review authority authorizes their removal or a final certificate of occupancy is issued, whichever occurs first.

4.    Shall ensure that any landscaping done in the protected zone subsequent to the removal of the barriers shall be accomplished with light machinery or hand labor.

5.    In addition to the above, the planning director may require the following:

a.    Cover with mulch to a depth of at least six inches or with plywood or similar material the areas adjoining the critical root zone of a tree in order to protect roots from damage caused by heavy equipment.

b.    Minimize root damage by excavating a two-foot-deep trench, at edge of critical root zone, to cleanly sever the roots of trees to be retained.

c.    Have corrective pruning performed on protected trees in order to avoid damage from machinery or building activity.

d.    Maintain trees throughout construction period by watering and fertilizing.

C.    Directional felling of trees shall be used to avoid damage to trees designated for retention.

D.    All construction activities, including staging and traffic areas, shall be prohibited within five feet of the dripline of the protected trees.

E.    Where tree retention areas are remote from areas of land disturbance and when approved by the planning director, alternative forms of tree protection may be used in lieu of the tree protection fencing; provided, that retained trees are completely surrounded with continuous rope or flagging and are accompanied by “Tree Save Area—Keep Out” signs.

F.    The review authority may require additional tree protection measures as conditions of approval, which are consistent with accepted urban forestry practices. (Ord. 2013-04 § 2 (Exh. A (part)), 2013)

18.180.080 Long-term tree protection and maintenance.

A.    The trees retained as required by this chapter shall be preserved and maintained as established in the conditions of the land development approval.

B.    The tree retention tract(s), open space tract(s) or other permanent protective mechanisms for tree retention shall be owned and maintained through a homeowners’ association or other common ownership. The face of the plat, binding site plan or similar document shall include a statement(s) that the project’s homeowners’ association or other common ownership will own and maintain the tree retention tracts, and enforce any activities contrary to the retention and preservation of the trees.

C.    The trees retained as required by this chapter may be removed to remedy a hazardous tree or public safety reasons only, and upon review and approval of the planning director and city arborist.

D.    Pruning of trees retained as required by this chapter may be permitted for maintenance and health of tree(s) or other justifications found acceptable by the city, and upon review and approval of the planning director and city arborist. (Ord. 2013-04 § 2 (Exh. A (part)), 2013)