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A. Standards. Significant tree preservation shall be required for any project permit.

1. A significant tree is an existing tree which:

a. When measured at four and one-half (4.5) feet above ground, has a minimum diameter of nine (9) inches for evergreen trees and deciduous trees;

b. When measured at four and one-half (4.5) feet above ground, has a minimum diameter of four (4) inches for Oregon white oaks (also known as Garry oaks); and

c. Regardless of the tree diameter, is determined to be significant by the Director due to the uniqueness of the species or provision of important wildlife habitat.

2. Tree Measurement. For the purposes of this section, existing trees are measured by diameter at four and one-half (4.5) feet above ground level, which is the usual and customary forest standard. Replacement trees are measured by diameter at six (6) inches above ground level, which is the usual and customary nursery standard.

3. Damaged or Diseased Trees. Trees will not be considered “significant” if, following inspection and a written report by a registered landscape architect, certified nursery professional or certified arborist, and upon review of the report and concurrence by the City, they are determined to be:

a. Safety hazards due to root, trunk or primary limb failure;

b. Damaged or diseased, and do not constitute an important wildlife habitat. At the discretion of the City, damaged or diseased or standing dead trees may be retained and counted toward the significant tree requirement, if demonstrated that such trees will provide important wildlife habitat and are not classified as a safety hazard.

Damaged or diseased Oregon white oaks shall comply with LMC 18A.70.310(D)(4) and 18A.70.330(B)(1)(a)(ii)(c) replacement requirements.

4. Preventive Measure Evaluation. An evaluation of preventive measures by an arborist in lieu of removing the tree and potential impacts of tree removal may be required. If required, this evaluation shall include the following measures:

a. Avoid Disturbing Tree. Avoid disturbing the tree at all unless it represents a hazard as determined by an arborist;

b. Stabilize Tree. Stabilize the tree, if possible, using approved arboricultural methods such as cable and bracing in conjunction with other practices to rejuvenate the tree such as repairing damaged bark and trunk wounds, mulching, application of fertilizer, and improving aeration of the tree root zones;

c. Pruning. Remove limbs from the tree, such as removing dead or broken branches, or by reducing branch end weights. If needed, remove up to one-quarter (1/4) of the branches from the canopy and main trunk only in small amounts, unless greater pruning is needed by approval of the arborist;

d. Wildlife Tree. Create a wildlife tree or snag, or cut the tree down to a safe condition, without disturbing the roots, where the tree no longer poses a hazard. To create snags, remove all branches from the canopy, girdle deciduous trees, and leave the main trunk standing. Wildlife trees or snags are most appropriate in City parks, greenbelts, vacant property, and environmentally critical areas;

e. Steep Slopes. Removal of tree roots on steep slopes may require a geotechnical evaluation;

f. Creeks and Lakes. Trees fallen into creeks and lakes are to remain in place unless they create a hazard; and

g. Provide professional recommendations on:

1. The necessity of removal, including alternative measures to removal;

2. The lowest-impact approach to removal;

3. A replacement tree plan, if required.

B. Trimming. Trimming of tree limbs and branches for purposes of vegetation management is allowed, provided the trimming does not cause the tree to be a safety hazard.

Utility pruning shall be conducted in accordance with the latest edition of the United States Department of Agriculture’s Publication NA-FR-01-95 How to Prune Trees, available at https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/fsbdev7_016046.pdf, except that tree pruning for utilities shall be conducted in accordance with the latest edition of the International Society of Arboriculture’s Best Management Practices – Utility Pruning of Trees, available at https://www.seattle.gov/light/vegetation-management/docs/Acrobat%20Document.pdf.

C. Preservation Criteria. All significant trees shall be preserved according to the following criteria:

1. Maximum Tree Removal on Developed Properties. Significant trees on existing single-family lots may be removed with a tree removal permit and without tree replacement, except Oregon white oaks which are regulated by LMC 18A.70.330, based on the following:

Maximum Tree Removal on Existing Single-Family Lots

Lot Size

Maximum number of significant trees allowed to be removed in 1 year

Maximum number of significant trees allowed to be removed in 5 years

*Lots up to 10,000 sq. ft.

N/A

N/A

Lots 10,001 to 30,000 sq. ft.

2

4

Lots 30,001 sq. ft. or greater

4

8

*LMC 18A.70.310(A) states that single-family lots up to 10,000 sq. ft. are exempted from tree preservation requirements.

2. Perimeter Trees. All significant trees within twenty (20) feet of the lot perimeter or required buffer, whichever is greater, shall be preserved; except that significant trees may be removed if required for the siting and placement of driveway and road access, buildings, vision clearance areas, utilities, sidewalks or pedestrian walkways, or storm drainage facilities and other similar required improvements, subject to the discretion of the Director.

3. Interior Trees. A percentage of all significant trees within the interior of a lot, excluding the perimeter area, shall be preserved within the applicable zoning district.

a. For new single-family residential development including a single-family dwelling on an individual lot, multifamily residential development, and public/quasi-public institutional development, fifty (50) percent of the significant trees located within the interior area of the lot shall be retained.

b. For new residential short subdivision or subdivision, all significant trees shall be retained and preserved except those required to be removed in order to construct streets, utilities, or other on-site improvements. Tree retention shall thereafter be provided on a lot-by-lot basis as the individual lots are developed. A tree survey shall be included as part of the subdivision application and a tree retention plan shall be recorded on the face of the plat to require compliance with this provision.

i. For any site proposed to be developed or cleared, at least fifty (50) percent of significant trees located outside the net buildable area plus any approved development footprint of the lot shall be retained if they are rated in good condition or better by an ISA certified arborist.

c. For commercial and industrial development, ten (10) percent of the significant trees located within the interior area of the lot, or individual lots in the case of subdivisions, shall be retained.

d. In Open Space and Recreation zones, ninety-five (95) percent of the significant trees located within the interior area of the lot shall be retained unless otherwise determined by the Director.

4. SEPA Requirements. Additional or specific tree retention may be required as SEPA mitigation in addition to the requirements of this section.

D. Tree Removal Permit Required. Approval is required prior to the removal of any significant tree (as described in subsection A of this section) in accordance with the following subsections E, F, and G of this section.

E. Tree Permits for Single-Family Residential Land Uses or Any Use When Not Associated With a Project Permit/Plan.

1. Criteria:

a. The applicant shall submit a complete application using the form provided and kept by the City.

b. The applicant shall confirm that the proposal complies with the requirements of this article.

2. Permit review process:

a. Applications and all submitted information will be verified and approved by City staff administratively.

b. If an application does not comply with any requirement in this section, the permit is subject to additional review by an ISA certified arborist and/or City staff. A tree retention plan may be required.

i. The Director shall review and may approve, approve with modifications, or deny a tree retention plan subject to the provisions of this section.

F. Tree Permits for Nonsingle-Family Residential Land Uses or Any Use When Associated With a Project Permit/Plan.

1. Submit a tree retention plan that consists of a tree survey that identifies the location, size and species of all significant trees on a site and any trees over three (3) inches in diameter at four and one-half (4.5) feet above ground level that will be retained on the site.

a. The tree survey may be conducted by a method that locates individual significant trees, or

b. Where site conditions prohibit physical survey of the property, standard timber cruising methods may be used to reflect general locations, numbers and groupings of significant trees.

c. Oregon white oaks that are to be retained on the site shall be indicated on the site plan with critical root zone protection per LMC 18A.70.330.

d. All other trees required to be preserved based on the preservation criteria in subsection C of this section shall be indicated in the site plan.

2. The tree retention plan shall also show the location, species, and dripline of each significant tree that is intended to qualify for retention credit, and identify the significant trees that are proposed to be retained, and those that are designated to be removed.

3. The applicant shall demonstrate on the tree retention plan those tree protection techniques intended to be utilized during land alteration and construction in order to provide for the continued healthy life of retained significant trees.

4. If tree retention and/or landscape plans are required, no clearing, grading or disturbance of vegetation shall be allowed on the site until approval of such plans by the City.

G. Heritage Tree Removal. The following criteria pertains only to those trees designated under LMC 2.48.040(D), heritage trees:

1. A tree removal permit is required for removal of any heritage tree(s);

2. City staff and an ISA certified arborist shall evaluate any heritage trees prior to a decision on the removal permit. Permit approval will be granted if an arborist report demonstrates that alteration or removal is necessary for health and safety, infrastructure operation, protection of existing buildings, or to accomplish reasonable use of property per state law. Recommendations for care, other than removal, will be considered.

H. Construction Requirements.

1. An area free of disturbance, corresponding to the dripline of the significant tree’s canopy, shall be identified and protected during the construction stage with a temporary three (3) foot high chain-link or plastic net fence. No impervious surfaces, fill, excavation, storage of construction materials, or parking of vehicles shall be allowed within the area defined by such fencing.

2. At Director’s sole discretion, a protective tree well may be required to be constructed if the grade level within ten (10) feet of the dripline around the tree is to be raised or lowered. The inside diameter of the well shall be at least equal to the diameter of the tree spread dripline, plus at least five (5) feet of additional diameter.

3. The Director may approve use of alternate tree protection techniques if the trees will be protected to an equal or greater degree than by the techniques listed above. Alternative techniques must be approved by a registered landscape architect, certified nursery professional or certified arborist, with review and concurrence by the City.

4. If any significant tree that has been specifically designated to be retained in the tree preservation plan dies or is removed within five (5) years of the development of the site, then the significant tree shall be replaced pursuant to subsection I of this section.

I. Replacement. When a significant tree subject to this section cannot be retained, the tree shall be replaced as a condition for the removal of the significant tree, in accordance with the following:

1. On-Site Replacement.

a. Based on DBH Size. Significant trees shall be replaced at a ratio of two to one (2:1) of the total diameter inches of all replacement trees to the diameter inches of all the significant trees removed.

b. Based on Canopy Coverage. The applicant may choose to plant fewer replacement trees than required by subsection (I)(1)(a) of this section if an ISA certified arborist determines in a written report that they will compensate for the canopy lost when they reach maturity and the resulting ratio is no less than one to one (1:1) of all replacement trees to the diameter inches of all the significant trees removed.

c. Based on Carbon (CO2) Reductions. The applicant may choose to plant fewer replacement trees than required by subsection (I)(1)(a) of this section if an ISA certified arborist determines in a written report that the trees planted and preserved on the property meet the following criteria:

i. Tree species to be planted on the site are selected for their optimal ability to sequester carbon and store it over the course of their lifetime, according to the latest and best science.

(a) Applicants shall provide an arborist report that demonstrates carbon sequestration value and calculations.

(b) The City will use i-Tree or a similar source provided by the applicant and validated through a third-party arborist, to confirm the data and calculation.

ii. Trees are planted in the optimal locations on the property, relative to the structures, to reduce energy use and therefore avoid CO2 emissions.

iii. The resulting replacement ratio is no less than one to one (1:1) of all replacement trees to the diameter inches of all the significant trees removed.

d. Replacement trees shall be no smaller than three (3) inches in diameter at six (6) inches above ground;

e. Existing healthy trees anywhere on the site which are retained to support the remaining significant trees can be counted against the on-site replacement requirements on a one to one (1:1) basis of the total diameter inches of all replacement trees removed, provided they meet the following criteria:

i. The tree does not present a safety hazard; and

ii. The tree is between three (3) and nine (9) inches in diameter at four and one-half (4.5) feet above ground.

f. For a minimum of five (5) years following completion of tree planting, all replacement trees shall be given the following care at a minimum:

i. Regular irrigation with deep watering during dry months to ensure proper establishment of the tree’s root system.

ii. Installation and maintenance of natural mulch material in a three (3) foot circle around the tree, with three (3) inches of depth, and not within three (3) inches of the trunk of the tree. Volcano mulching is an improper tree care method and should not be used.

iii. Maintenance and pruning using ANSI A300 tree care standards.

2. Each significant tree that is located interior to the twenty (20) foot perimeter area, and which is in excess of the significant tree percentage that is required to be retained, may be credited towards replacement on a one and one-half to one (1.5:1) basis of the total diameter inches for any perimeter trees required to be removed for development, provided the interior tree is between nine (9) inches and twenty-four (24) inches in diameter for evergreen trees, or between nine (9) inches and thirty (30) inches in diameter for deciduous trees.

3. Each significant tree that is located interior to the twenty (20) foot perimeter area, and which is in excess of the significant tree percentage that is required to be retained, may be credited towards replacement on a two to one (2:1) basis of the total diameter inches for any perimeter trees required to be removed for development, provided it meets one of the following criteria:

a. The tree exceeds sixty (60) feet in height, or twenty-four (24) inches in diameter for evergreen trees, or thirty (30) inches in diameter for deciduous trees.

b. The tree is located in a grouping of at least five (5) other significant trees with canopies that touch or overlap.

c. The tree provides energy savings, through wind protection or summer shading, as a result of its location relative to buildings.

d. The tree belongs to a unique or unusual species.

e. The tree is located within twenty-five (25) feet of any critical area or required critical area buffers.

f. The tree is eighteen (18) inches in diameter or greater and is identified as providing valuable wildlife habitat.

4. Off-Site Replacement. When the required number of significant trees cannot be physically retained or replaced on site, the applicant may have the option of:

a. The planting of the required replacement trees at locations approved by the Director throughout the City. Plantings shall be completed prior to completion of the project permit requiring tree replacement.

b. Payment in lieu of replacement may be made to the City Tree Fund for planting of trees in other areas of the City. The payment of an amount equivalent to the estimated cost of buying and planting the trees that would otherwise have been required to be planted on site, as determined by the City’s Tree Replacement Cost Schedule. Payment in lieu of planting trees on site shall be made at the time of the issuance of any building permit for the property or completion of the project permit requiring the tree replacement, whichever occurs first.

J. Incentives for Preservation. Significant tree preservation is incentivized as outlined in the following chart. All projects utilizing the following preservation incentives shall demonstrate compliance with subsections (F) and (H) of this section to ensure protection of the tree during site construction.

Tree Preservation Incentives

Incentive

Code Sections

Description

Code Language

Parking Reduction

LMC 18A.80.060, Parking incentives

Chapter 18B.600 LMC, Parking

Chapter 18C.600 LMC, Parking

Allow for alternative standards to protect significant trees, e.g., alter parking dimensional standards or rates.

Credit for preservation of significant or heritage trees. For every significant tree and/or heritage tree preserved within the property, the required number of parking spaces may be reduced by one-half (0.5) spaces, provided the total reduction does not exceed five (5) percent of the total required parking spaces, when combined with all parking incentive credits.

Density Increase

LMC 18A.60.110, Density standards

LMC 18B.200.230, District-Wide Development Standards

LMC 18C.200.230, District-wide development standards

Increase density if retaining significant trees, with special attention given to areas experiencing the urban heat island effect and/or low tree equity.

For multifamily uses, maximum density may increase by one (1) unit for each significant tree preserved on a property that is located in the Downtown District (not to exceed more than twenty (20) percent of the total allowable units).

Bonus density, where applicable, shall be computed by adding the bonus units authorized by LMC 18A.90.050 to the base units computed under this section.

For multifamily use types, maximum density may increase by one (1) unit for each significant tree preserved on a property that is located in a census tract with a tree equity score of under the City’s 2018 average score of sixty-nine (69) (not to exceed more than twenty (20) percent of the total allowable units).

Master Plan Flexibility

LMC 18B.700.720, Master Planned Development – Town Center Incentive Overlay

Allow flexibility in a master plan if retaining significant and/or heritage trees, with special attention given to areas experiencing the urban heat island effect and/or low tree equity.

Master planned development allows flexibility and variation design as long as there is a net benefit to the City. Significant and heritage tree preservation shall be included as a benefit under the master planned development required net benefit findings in LMC 18B.700.720(G)(3).

Landscaping Reduction for Oregon White Oak Preservation

LMC 18A.70.150, Landscaping types

Allow for a reduction in the Type I vegetative buffer landscaping requirements for the preservation of Oregon white oaks.

A credit of one and one-half (1.5) square feet of vegetative buffer shall be given for every square foot of area devoted to new or the preservation of Oregon white oak tree use.

Building Setback Reduction

LMC 18A.60.030, Residential area and dimensions

LMC 18A.60.070, Open space area and dimensions

Allow for a reduction in the rear yard and/or side yard building setback requirements for the preservation of significant trees.

The Director may reduce a rear yard and/or side yard building setback to compensate for significant or heritage tree preservation; provided, that the setback is not reduced more than five (5) feet, is no closer to the property line than three (3) feet, is the minimum reduction required for tree preservation, and complies with LMC 18A.60.100, Building transition area.

Impervious Surface Bonus

LMC 18A.60.030, Residential area and dimensions

LMC 18A.60.040, Commercial area and dimensions

LMC 18A.60.070, Open space area and dimensions

Allow an increase in allowable impervious surface on a site where a significant tree is being preserved. Impervious surface cannot be located within the critical root zone of the preserved tree(s).

The Director may increase the amount of allowable impervious surface by five (5) percent to compensate for the preservation of a significant or heritage tree.

K. Enforcement

1. Failure to comply with any lawful order issued under the authority of this title constitutes a Class 2 civil infraction, as defined in Chapter 1.48 LMC. Any violation of this title which is deemed to be a public nuisance or a danger to the public health and/or safety shall be addressed as specified in Chapter 1.44 LMC.

2. Malicious Cutting. Malicious cutting may result in tripling of the amount of replacement value as provided in subsection (I)(4) of this section. [Ord. 775 § 1 (Exh. A), 2022; Ord. 726 § 2 (Exh. B), 2019.]