Chapter 2.43
TREE RETENTION AND REPLACEMENT FOR PUBLIC PARK SPACES
Sections:
2.43.040 Tree removal and pruning requirements.
2.43.050 Tree retention requirements.
2.43.070 Tree replacement requirements.
2.43.080 Fee in lieu of replacement.
2.43.090 Monitoring, enforcement and penalties.
2.43.010 Purpose.
The purpose of this chapter is to establish standards for tree retention and replacement on properties owned by the City and managed by the City of SeaTac Parks and Recreation Department, in support of the City’s urban forestry, climate, and equity goals.
These efforts promote no net canopy loss and equitable canopy coverage across public parks, reduce the impacts on stormwater systems and natural habitats, absorb wind and noise, improve air quality, conserve water resources, help keep parks cool and increase privacy and comfort in public areas. (Ord. 25-1025 § 1 (Exh. A))
2.43.020 Applicability.
This chapter applies only to trees on public park lands owned, managed and maintained by the SeaTac Parks and Recreation Department. It does not apply to trees on private properties, rights-of-way maintained by the Public Works Department, or other City-owned facilities unless explicitly stated.
Removal of trees on public park lands leased from the Port of Seattle, the Port of Seattle’s agents or contractors is applicable to prevent the creation of tree obstructions to airplane navigation or airport hazards, to remove such tree obstructions or airport hazards as may come to exist, or for the safe and efficient operation of Seattle-Tacoma International Airport. (Ord. 25-1025 § 1 (Exh. A))
2.43.030 Definitions.
Construction. In this chapter, “construction” pertains to any equipment used to remove significant trees during capital improvement projects, tree obstructions within the Flight Corridor Management (Safety) Program, or upon approval by the Parks and Recreation Director.
“Critical root zone” means an area around the tree equal to one (1) foot radius from the center point of the tree for each one (1) inch of tree trunk diameter measured at the diameter at standard height (DSH). For example, a tree with a twenty (20) inch diameter at standard height would have a CRZ with a twenty (20) foot radius and a forty (40) foot diameter.
“Diameter at standard height (DSH)” means measured at four and a half (4.5) feet above grade using fabric logger’s tape or using a standard fabric measuring tape and dividing by pi (3.14) to obtain the diameter.
“Hazard tree” means a tree or tree part that poses a high risk of failure or damage to persons; and
A hazard tree (or tree part) is assessed by a qualified professional and is typically defined by a certain overall risk rating using the International Society of Arboriculture (ISA) Tree Risk Assessment method in its most current form.
“Qualified tree professional” means an individual who possesses the necessary education, training, certification, and/or licensure to competently perform arboricultural or tree risk assessment services. This includes, but is not limited to:
1. A certified arborist credentialed by the International Society of Arboriculture (ISA) or an equivalent nationally or internationally recognized organization;
2. A professional holding the Tree Risk Assessment Qualification (TRAQ) issued by the ISA or equivalent credentials;
3. Other individuals with equivalent certification, licensure, or documented expertise in forestry, arboriculture, horticulture, or a related field, who are recognized by regulatory agencies or professional organizations as competent to assess and manage tree health and safety.
“Significant tree” means an existing healthy tree which, when measured at diameter at standard height (DSH), has a minimum diameter of:
1. Eight (8) inches for evergreen trees; or
2. Twelve (12) inches for deciduous trees (excluding poplar trees).
“Tree canopy coverage” means the area of ground covered by the branches and leaves of trees, expressed as a percentage.
“Tree density” means the number of trees within a given area, expressed as trees per acre.
Tree Obstruction. In this chapter, Washington State law expressly identifies tree obstructions that “in effect reduce the size of the area available for the landing, taking off, and maneuvering of aircraft thus tending to destroy or impair the utility of the airport and the public investment therein” as “airport hazards.”
“Tree protection zone” means an area sufficient to protect the tree during and after construction as recommended by a qualified tree professional. (Ord. 25-1025 § 1 (Exh. A))
2.43.040 Tree removal and pruning requirements.
A. No person may damage or remove a tree from City properties managed by the Parks and Recreation Department without written authorization from the Parks and Recreation Director or designee.
B. The following activities shall also require written authorization from the Parks and Recreation Director or designee.
1. Major pruning (more than twenty-five percent (25%) of canopy). The City may require that the pruning be performed by a qualified tree professional (certified ISA arborist).
2. Tree topping is not standard practice. Trees severely damaged by storms or other causes, or where other pruning practices are impractical, may be exempted from this section at the determination of the Director of the Parks and Recreation Department.
C. Exceptions. The following activities are exempt from the requirements of subsections (A) and (B) of this section:
1. Emergency removal of trees by the Parks and Recreation Department, emergency responders, or utility providers in situations involving immediate and significant danger to life, property, interruption of utility services, or public safety.
2. Routine maintenance conducted by Parks staff or authorized contractors that does not involve major pruning or removal of trees such as deadwood trimming, trail clearance, or groundcover management.
3. Removal of trees as part of capital improvement projects, with replacement requirements in SMC 2.43.070.
4. Removal of trees by the Port of Seattle pursuant to RCW 14.12.020; provided, that the Port gives the City a minimum of one hundred eighty (180) days’ advance notice and complies with the requirements of SMC 2.45.070 or 2.45.080.
5. Removal of invasive species or restoration-related vegetation clearing conducted as part of an approved ecological stewardship or habitat restoration plan as determined by the City’s Urban Forester. (Ord. 25-1025 § 1 (Exh. A))
2.43.050 Tree retention requirements.
A. Construction on Public Property. Alternative placement of trails, roads, and other structures shall be considered to avoid loss of mature trees prior to construction plan approval.
B. Tree Density Credits. Tree density credits are a way to quantify the amount of trees on a property. Each tree is assigned a certain number of credits based on its size and taxonomy, and the total number of credits on a site is calculated.
1. Only healthy trees can be used to satisfy the required minimum tree credits.
2. Trees on the City of SeaTac Discouraged Tree List cannot be used to satisfy the required minimum tree credits.
C. For sites with existing healthy significant trees, a minimum percentage of tree credits shall be from retained trees. The remainder may be from retained trees or newly planted trees. To ensure that existing trees are appropriately retained as construction activities occur, fifty percent (50%) of required tree credits must be achieved through retention of existing trees, except in the following circumstances:
1. If the lot does not have sufficient significant trees to meet the tree retention requirements, then any existing healthy trees shall be retained.
D. Tree Density Credit Calculation.
|
DSH: |
3" – 5" |
6" – 10" |
12" |
14" |
16" |
18" |
20" |
22" |
24" |
26" |
28" |
30" |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Tree Credits: |
0.5 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
1. Existing native conifer trees listed on the City of SeaTac’s Approved Tree list receive two (2) tree credits.
2. Existing native deciduous trees listed on the City of SeaTac’s Approved Tree list receive one and one-half (1.5) tree credits.
3. Non-native trees receive one (1) tree credit.
4. Divide the square footage of the subject lot by forty-three thousand five hundred sixty (43,560) (square footage of one (1) acre). The resulting number is then multiplied by fifty (50) (the minimum tree credit requirement for one (1) acre). In calculating required tree credits, any fraction of credits shall be rounded up to the next whole number from a one-half (0.5) or greater value.
5. The retention of native trees shall be prioritized over non-native trees by maximizing the number of tree credits for native trees on a given lot.
Example: a ten (10) acre lot (four hundred thirty-five thousand six hundred (435,600) square feet) would need five hundred (500) tree credits to meet the minimum retention requirements (435,600/43,560 = 10; 10 × 50 = 500 tree credits).
By prioritizing native trees, the tree density for the lot may be met by retaining twenty-nine (29) native conifer trees measured at twenty-four (24) inches DSH (29 native conifer trees × 2 credits × 8 tree credits = 464 tree credits) and four (4) native deciduous trees measured at twenty (20) inches DSH (4 native deciduous trees × 1.5 credits × 6 tree credits = 36 tree credits), for a total of five hundred (500) tree credits.
6. Additional prioritization shall be considered for native conifer species. Upon tree credit calculation, native conifer trees shall be retained at three (3) coniferous to every one (1) deciduous tree. (Ord. 25-1025 § 1 (Exh. A))
2.43.060 Tree protection.
A. Protection of Tree Health. Tree protection during construction, restoration, or establishment involves safeguarding trees from damage, stabilizing for initial growth, or mitigating hazards in natural areas that could potentially harm trees. This includes protecting their roots, trunk, and branches from injury, compaction, and other harm that can result from activities.
1. Under certain circumstances, disturbing or cutting roots in a critical root zone may be unavoidable. In such cases, the work should be done only under the on-site supervision of the Urban Forester or other ISA certified arborist.
a. When necessary to cut roots more than four (4) inches wide, a clean cut with sharpened hand tools is preferred. Large equipment or other dull instruments are not authorized.
2. Stakes or guards may be placed alongside or around any tree; provided, that such supports are placed as near as practical to the tree for which support is intended, and do not restrict access to or from the protection site that creates any hazard to the public;
3. Cages or other structures that protect against wildlife browsing during initial establishment may also indicate sites in areas of heavy human activity.
a. All supports, cages, or other structures shall be removed after one (1) year of installation, or when causing damage to the tree.
B. Protection of Significant Trees. To provide the best protection for significant trees, personnel, at minimum:
1. Shall provide during the construction, restoration, or establishment phase either:
a. A temporary five (5) foot high fence; or
b. A line of five (5) foot high, orange-colored, two-by-four (2×4) stakes placed not more than ten (10) feet apart.
2. Shall place the fence or stakes in a line generally corresponding to the drip line of any significant tree(s) to be retained.
3. Shall not install impervious surfaces, excavate, store, or drive equipment within the area defined by such fencing or stakes.
4. Shall not lower the grade level within the larger of the two (2) areas defined as follows:
a. The drip line of the tree(s); or
b. An area around the tree equal to one (1) foot diameter for each inch of tree trunk diameter measured four and one-half (4.5) feet above the ground.
5. May use alternative protection methods if determined by the Urban Forester to provide equal or greater tree protection. (Ord. 25-1025 § 1 (Exh. A))
2.43.070 Tree replacement requirements.
A. Tree Selection Criteria.
1. Replacement trees shall, at the determination of the City, prioritize species for replacement plantings, as shown on the City of SeaTac’s Approved Tree List.
a. Native and climate-resilient trees.
b. Canopy spread.
c. High-performing regenerative species to support regeneration of other species.
d. Replacement trees of similar size and function to tree/s removed.
2. The location and type of on-site replacement trees shall be determined by a qualified tree professional using “Right tree, right place” principles, or site conditions must be modified to create the right place for the right tree.
3. Mature height of trees replaced within the Flight Corridor Management Program zone will be considered when selecting replacement species to minimize future removal of tree obstructions.
4. If the provisions contained in this section cannot be met, the applicant shall comply with SMC 2.43.080, Fee in lieu of replacement.
5. Replacement trees must be planted during fall or winter season.
6. Trees listed on the City of SeaTac’s Discouraged Tree List shall not be considered replacement trees.
7. The Urban Forester shall approve the final tree species selected.
B. Tree Replacement. Trees removed pursuant to the provisions of this chapter must be replaced unless otherwise stated.
For tree removal associated with an approved landscape or construction plan, replacement trees shall be prioritized on site to maintain or increase tree density and canopy coverage. Where on-site replacement is not feasible, off-site replacement may be considered based on tree equity needs. Replacement trees must be provided at a replacement no less than:
1. A four to one (4:1) replacement ratio must be met for significant trees measuring below twenty (20) inches DSH. For every one (1) significant tree removed, at least two (2) of the four (4) replacement trees shall be native conifer trees. The remaining two (2) replacement trees may be either deciduous or coniferous; or
2. Based on a tree replacement credit table:
|
DSH: |
≤ 20" |
> 20" up to 22" |
> 22" up to 24" |
> 24" up to 26" |
> 26" up to 28" |
> 28" up to 30" |
|---|---|---|---|---|---|---|
|
Tree Credits: |
7 |
8 |
9 |
10 |
11 |
12 |
a. Native conifer trees on the City of SeaTac Approved Tree list shall receive two (2) tree credits.
b. Native deciduous trees on the City of SeaTac Approved Tree list are worth one and one-half (1.5) tree credits.
c. Any tree removed measuring between a listed DSH shall be rounded up to the next increment (example: a tree measuring at twenty and one-half (20.5) inches DSH shall be considered twenty-two (22) inches to determine its replacement credits).
d. All replacement trees must meet the minimum size as described in subsection (F) of this section, Minimum Size.
Example: A significant tree measuring twenty-four (24) inches DSH has a minimum replacement value of ten (10) credits. Replacement can be met by planting five (5) native conifer trees (5 trees × 2 tree credits = 10).
C. Exception. For parks with existing healthy significant trees, a minimum of forty percent (40%) tree canopy coverage must be met through planting and maintenance within each public park space.
1. If the overall canopy coverage of existing trees on the site before construction is above forty percent (40%) based on the most recent LIDAR data, replacement may be met through fee in lieu of replacement per SMC 2.43.080 at the discretion of the Parks and Recreation Director.
2. A combination of planting and fee in lieu of replacement may be allowed at the discretion of the Parks and Recreation Director and Urban Forester.
D. Tree Replacement Maintenance and Quality. Replacement trees must be State Department of Agriculture Nursery Grade No. 1 or better and must be consistent with an approved tree plan. Replacement trees must be mulched and protected.
1. Soil shall be loosened within the planting hole three (3) times the widest dimension of the root ball;
2. The top of the root ball shall be placed at finished grade and four (4) inch-high soil or berm shall be constructed around the root ball edge;
3. The root ball shall be placed on existing or recompacted soil to prevent settling;
4. Six (6) inches of woodchip or bark mulch shall be placed over the loosened soil, tapering so no woodchip or bark mulch touches the tree trunk; and
5. Organic matter or fertilizer shall be incorporated with native soils as needed according to best management practices;
6. Trees replaced by external agencies shall be responsible for the installation and maintenance of each tree over five (5) years. Maintenance shall include the following:
a. Water: Apply a minimum of two (2) gallons of water per plant (five (5) gallons for sun exposed plants), per visit, to recently planted native plants to achieve a soil saturation of twelve (12) inches’ depth. Water sites weekly at a rate of one (1) to two (2) gallons at a time to allow for adequate absorption.
b. Mulch: At least six (6) inches of weed-free mulch shall be maintained during the establishment phase.
c. Vegetation management: Clearing around tree wells a diameter of at least ten (10) feet.
d. Mortality of replacement trees: If a replacement tree dies, an additional tree must be planted and the five (5) year maintenance schedule restarts. The Urban Forester shall track all changes and updates to monitor each replacement tree.
E. Replacement Trees.
1. Replacement trees must be planted during fall or winter planting seasons; and
2. Trees must meet the minimum caliper or gallon size standards described in subsection (F) of this section.
F. Minimum Size.
1. Native deciduous trees: two (2) inch caliper; and
2. Native conifer trees: two (2) inch caliper at six (6) feet in height. (Ord. 25-1025 § 1 (Exh. A))
2.43.080 Fee in lieu of replacement.
A. The fee in lieu of replacement is calculated from the individual tree’s economic value and based on the most current iTree’s MyTree data over twenty (20) years in “good” condition, administration and labor costs derived from the City of SeaTac’s most recent fee schedule (Standard Hourly Rate).
B. The applicant shall pay the fee in-lieu amounts to the City of SeaTac upon completion of a site inspection and confirmation.
C. Fee in-lieu funds may be allocated to support the City of SeaTac’s urban forestry efforts in alignment with the goals outlined in the Green SeaTac Partnership Urban Forest Stewardship Plan and future urban forestry plans at the discretion of the Parks and Recreation Director or designee. On-site restoration efforts such as noxious weed removal and planting of native trees and shrubs will be prioritized when the minimum canopy coverage goal of forty percent (40%) is met. These funds may also be used for a range of urban forestry-related activities, including but not limited to ecological restoration, enhancement of urban forest areas, and off-site tree plantings, prioritizing tree equity and areas with limited tree canopy coverage.
D. Fee in-lieu funds may support off-site tree replacement plantings in City-owned parks, public green spaces and natural areas in line with the City’s tree canopy and equity goals. All off-site tree replacements must comply with the replacement standards specified in SMC 2.43.070. (Ord. 25-1025 § 1 (Exh. A))
2.43.090 Monitoring, enforcement and penalties.
Authority. The Parks and Recreation Director or designee shall be responsible for ensuring compliance with these standards. All pruning, removal, or replacement activities shall be tracked through a Parks-maintained urban forest inventory system and verified through site inspections conducted by the Urban Forester.
A. Routine monitoring of planting and restoration sites should be conducted to track the condition and health of reforested sites and gauge progress.
1. Plant survival rates shall be tracked quarterly and other methods for replanting or restoration shall be considered if the survival rate decreases by ten percent (10%) or more.
B. Penalties. It is unlawful to remove or damage trees located on public park properties. Tree removal or damage shall be through either direct or indirect actions, including but not limited to:
1. Clearing, damaging, girdling, or poisoning, in each case resulting in an unhealthy or dead tree;
2. Topping that results in removal of more than twenty-five percent (25%) of the live crown; or
3. Damage to roots or trunk that is likely to destroy the tree’s structural integrity.
C. Fines. Civil penalty fines shall be assessed in accordance with the Civil Penalty Fines table based on the diameter at standard height of the unlawfully removed or damaged tree trunk. If the DSH of the unlawfully removed or damaged tree cannot be established, the diameter of the remaining stump shall be used in lieu of DSH. In cases where the stump has been removed, the City shall assess a ten-thousand-dollar ($10,000) penalty fine per unlawfully removed tree.
|
Unlawfully Removed or Damaged Tree DSH or Stump Diameter |
Fines Per Tree |
|---|---|
|
Trees less than 8 inches |
$700 |
|
Larger than 8 and up to 10 inches |
$1,000 |
|
Larger than 10 and up to 14 inches |
$2,000 |
|
Larger than 14 and up to 18 inches |
$4,000 |
|
Larger than 18 and up to 22 inches |
$6,000 |
|
Larger than 22 and up to 26 inches |
$8,000 |
|
Larger than 26 and up to 30 inches |
$16,000 |
|
Larger than 30 inches |
$20,000 |
|
Tree stump has been eliminated |
$10,000 |
A Code Enforcement Officer may permit a violator of this chapter to voluntarily perform City-approved community service in lieu of paying some or all of the civil penalty. Community service may include restoration or educational programs. The amount of community service shall reasonably reflect the comparable value of the civil penalties imposed. (Ord. 25-1025 § 1 (Exh. A))