Bothell, WA Tree Protection: Protected Tree Species (2026)
Key Facts
- Protected size
- Over eight inches across, measured four feet above grade
- Excluded trees
- Alders and cottonwoods
- Retention in R-C, R-L1, R-L2
- At least 20 percent of total diameter inches
- Retention in R-AC, DC, DN, DT, GDC
- 15 percent of site diameter inches
- Disturbance-free area
- Dripline or 15 feet from trunk, whichever is greater
- Retention bond
- $2,000 to $20,000 per retained tree, by diameter
Summary
In the City of Bothell, Washington, tree protection under Bothell Municipal Code § 12.18.030 turns on size, not species. A significant tree is an existing tree over eight inches in diameter, measured four feet above grade, inside the net buildable area, and alders and cottonwoods are excluded. Development applications must carry a tree retention plan and keep a set share of the diameter inches.
B. Applicable Activities. Tree retention shall apply to developments where any human-caused change to improved or unimproved real estate, including, but not limited to, construction of buildings or other structures, dredging, filling, grading, paving, excavation, or other land-altering activities, are proposed or may be occurring. For the purposes of this chapter, vegetation retention shall apply to significant trees, which shall mean existing trees over eight inches in diameter (excluding alders and cottonwoods) as measured four feet above grade, that are located within the net buildable area of a subject property as described within BMC 12.14.030 and 12.14.040. ... C. These tree retention requirements shall not apply to existing individual single-family dwellings on lots of record that are 20,000 square feet or less in area, or duplexes, multiple-family residential or nonresidential developments having less than 2,000 square feet of required landscaping over the entire development area.
Full Breakdown
Chapter 12.18 BMC protects significant trees: existing trees over eight inches in diameter, excluding alders and cottonwoods, measured four feet above grade inside the net buildable area of the property. The rules attach to developments involving construction, dredging, filling, grading, paving, excavation, or other land-altering activities. Existing individual single-family dwellings on lots of record of 20,000 square feet or less are exempt, as are duplexes and multiple-family or nonresidential developments with less than 2,000 square feet of required landscaping over the entire development area.
Every other development application needs a tree retention plan prepared by a qualified professional such as a licensed landscape architect, licensed or certified forester or arborist, or Washington State certified nurseryperson. The plan lists the location, size, species and driplines of significant trees and describes protection methods such as a minimum four-foot-high chainlink or plastic-net fence around driplines. The disturbance-free area runs to the dripline or at least 15 feet from the trunk, whichever is the greater distance.
Retention targets are zone-specific. In R-C, R-L1 and R-L2, at least 20 percent of the total diameter inches of significant trees must be retained. In R-M1 through R-M4 the figure is also 20 percent, but retaining 15 percent in significant trees plus up to five percent in smaller trees, or installing new trees, satisfies it, with each new tree counted as two diameter inches. In R-AC, DC, DN, DT and GDC the requirement is 15 percent of the site diameter inches, with replacement options such as one new coniferous tree at least 20 feet tall at planting for each significant tree.
The selection of which trees stay follows stated objectives, including continuous overstory canopies, groupings or mutually supporting groves, protecting trees adjacent to critical area buffers, and retaining trees with the best chance of survival after development.
Violations & Fines
Trees designated for retention that die, are damaged, or are removed during development trigger a restoration plan that must be approved before occupancy permits issue or bonds are released. Replacement is two coniferous trees at least 20 feet tall, or four at least 14 feet tall, for each significant tree; deciduous replacements are two trees of four inches in diameter or four of two and one-half inches. The city has the option of enforcing the bond, and BMC 11.20.010 sets civil penalties up to $250.00 per day.
Frequently Asked Questions
Which trees count as protected in Bothell?
Does the retention rule apply to my existing house?
How close can I dig or grade to a retained tree?
What bond protects trees during construction?
Sources & Official References
Other rules in Bothell
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Protected Tree Species in Nearby Cities
How other cities in King County handle protected tree species.