Chapter 25.120
TREE RETENTION
Sections:
25.120.040 Oak management mapping units.
25.120.060 Repealed.
25.120.010 Purpose.
(1) The purpose of this chapter is to:
(a) Protect natural habitats, air quality, and ground water recharge;
(b) Improve the appearance of the community;
(c) Provide shade and wind protection;
(d) Reduce stormwater discharge; and
(e) Conserve water supplies.
(2) This chapter is intended to help achieve these purposes by:
(a) Retaining trees, without reducing developmental densities from those indicated in the comprehensive plan. (Ord. 02-707 § 1)
25.120.020 Applicability.
This chapter shall apply to street trees throughout the city and to all new development projects that require a site plan approval, subdivision, or short plat. (Ord. 02-707 § 1)
25.120.030 Tree retention.
(1) Tree retention shall constitute an integral design goal in all public and private site design processes. Retention is particularly desired for trees that are especially large, well-formed, historic, grouped, close to a sensitive area, visually prominent, part of a recognizable landmark, or valuable as wildlife habitat.
(2) All landmark (see DMC 25.10.120, L definitions) Oregon white oak trees shall be retained, along with any native understory within a protection zone one and one-half times the radius of the oak’s canopy, unless the landmark oaks are within a proposed street right-of-way which is integral to the neighborhood and cannot reasonably be moved, or unless overall neighborhood densities cannot be met. In such cases, up to 30 percent of the landmark oak trees may be removed, when consistent with the standards in the table of DMC 25.120.040(1). At least half of all other (non-oak) landmark trees shall be retained. In the industrial district and manufacturing/research park district, landmark trees which are in the building footprint, parking lot or storm retention area may be removed; provided, that tree retention is achieved along street boundaries and when abutting a residential district.
(3) The following minimum number of trees (other than street trees) per acre, expressed as an average over the entire neighborhood plan, site plan, subdivision, or short plat, shall be retained; provided, that nothing in the following shall require the retention of more than half of the existing trees, other than oak:
(a) Business and technology, and manufacturing/research: one and one-half;
(b) Commercial, office, mixed, civic, and schools: three;
(c) Single-family and mixed single-family and multifamily areas: four; provided, that for multifamily uses, half of the required four retained trees per acre may be satisfied by installing new trees; further provided, the cumulative diameter at breast height of the new trees equals that of the trees that would otherwise be retained but which are to be removed.
(4) When the application before the city contains oak management mapping units, trees retained therein shall count toward meeting the above requirement.
(5) No clearing, grading, trenching, cutting, impervious surfacing, or other construction shall be allowed within the drip line of any tree to be retained, or within one and one-half times the radius of the canopy in the case of oak trees to be retained, nor shall grades be lowered or raised so near as to jeopardize said trees; unless there is no other alternative and the intrusion is the minimum possible as determined by the administrator. Temporary barriers shall be installed around trees requiring protection during construction.
(6) All landscape plans required by DMC 25.90.060 shall include:
(a) The location, size, and species of all landmark, historic, and specimen trees;
(b) Which trees are to be retained; and
(c) How retained trees will be protected during development.
(7) All trees retained by means of this chapter, including those on single-family residential lots, shall remain protected for their life, except as noted in subsection (8) of this section. The plat or site plan on which the tree is located shall contain the following note: “This plat is also subject to an approved tree retention plan which requires that certain trees be preserved. That plan, which is binding on all owners, is on file with the City Planning Department.” To further inform future lot owners, a copy of the approved tree retention plan shall be provided each owner at closing on each lot.
(8) Trees required to be retained by this chapter shall not be removed unless the administrator determines in writing that they have become hazardous or diseased or threaten to damage public or private property. Whoever removes a street tree or required tree shall replace it with a tree approved by the city.
(9) Additional tree retention requirements for areas adjacent to the Puget Sound Bluff in Hoffman Hill Village may be found in Section II.B.2 of the Settlement Agreement for Lone Star Northwest DuPont Project dated December 25, 1994. Additional tree retention requirements for areas of the Puget Sound Bluff north of Sequalitchew Creek and along the north side of Sequalitchew Creek may be found in Exhibit A to Ordinance 95-521, page 36, section 9. (Ord. 07-834 § 1; Ord. 02-707 § 1)
25.120.040 Oak management mapping units.
(1) DuPont’s groves of Oregon white oaks constitute a unique resource demanding separate treatment. Accordingly, in 1996, Jones & Stokes Associates, Inc., prepared oak management recommendations under contract to the city. To implement those recommendations, the following mapping units are hereby established. Exhibit A attached to the ordinance codified in this chapter and found on file in the office of the city clerk shows their location. The regulations pertaining to these mapping units are as follows:
|
Mapping Units per Oak Management Recommendations |
Area of Mapping Unit That Must Be Preserved |
Which Portions of Mapping Units to Preserve |
|---|---|---|
|
O-3, O-4, O-5a |
100% |
All |
|
O-1, MO-2, MO-13 |
80% |
For O-1 and MO-2, the oak preserves shall be focused in the core areas identified in the above-cited Oak Management Recommendations, and shall be in blocks no less than 200 feet wide between areas of developable land. For MO-13, the oak preserve shall be one contiguous block including the entire western portion thereof. |
|
MO-1b |
50% |
The oak preserve shall be in a contiguous block at least 100 feet wide between areas of developable land. Also, the oak preserve shall be located to help implement the open space corridor which the comprehensive plan designates in that area. |
|
O-2, O-5b, O-6, MO-17b, MO-18 |
30% |
For O-5b, O-6, and MO-18, the oak preserves shall be focused in the core areas identified in the above-cited Oak Management Recommendations. For MO-17b, the oak preserve shall be in the 200-foot-wide buffer area adjoining Edmond Marsh. |
|
MO-17a |
20% of canopy (not of mapping unit) |
The oak preserves shall be incorporated into pedestrian walkways, parks, natural landscaping, or road corridors. The largest oaks, or groups of oaks, shall be preserved. The protection zone around oaks or groups of oaks shall be at least one and one-half times the radius of the crown of the tree. |
(2) Areas preserved per the above requirement shall be known as oak preserves.
(3) Temporary fences shall be placed around oak preserves during construction to avoid disturbance.
(4) No cuts, fills, or trenching shall occur in oak preserves. Grading near oak preserves shall utilize natural contours when possible to avoid creating pedestals or bodies where oaks are growing.
(5) Oaks in preserves shall not be irrigated unless an arborist experienced with oaks determines that, due to drought, they need deep watering around the drip line. Oak trees in areas surrounded by impervious surfaces may be more susceptible to drought.
(6) Landscaping in oak preserves shall be limited to native shrubs, grasses, or herbs. In Mapping Unit MO-17a’s preserves, native understory shrubs such as snowberry may be planted.
(7) The owners of oak preserves shall remove nonnative shrubs therein, such as Scot’s broom.
(8) Douglas firs shall be removed in oak preserves as needed to ensure oak survival, except that, in MO-13, Douglas firs shall not be removed or topped unless an arborist experienced with oaks determines they are growing within the crown of oak trees and significantly affecting the oaks’ growth.
(9) Oak preserves shall not be mowed except in Mapping Unit MO-17a, and in any oak preserve as necessary for fire control or for Scot’s Broom control.
(10) Oaks in preserves shall not be cut, but may be pruned by an arborist experienced with oaks, during the dormant season, to remove dead, weakened, diseased, or dangerous branches. (Ord. 02-707 § 1)
25.120.050 Modifications.
Anyone with an ownership interest in land may request a modification from the provisions of this chapter based on special circumstances pertaining to that land or the trees on it. Such requests shall be addressed, in writing, with full documentation and justification, to the administrator, who shall grant or deny based on DMC 25.120.010. Such request shall be processed with a Type III procedure per DMC 25.175.010(4). (Ord. 05-790 § 8; Ord. 02-707 § 1)
25.120.060 Appeals.
Repealed by Ord. 05-790. (Ord. 02-707 § 1)