A. Purpose. The retention of existing vegetation such as intact forest areas is an important component of the city’s character, and assists the city in meeting its aesthetic, surface water, and environmental policies within the Imagine Bothell… Comprehensive Plan. Existing vegetation may also be used to meet all or portions of the landscaping requirements within this chapter.
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.
D. All proposed development applications not specifically excepted as outlined in subsection C of this section shall include a tree retention plan for the entire subject property identifying and locating all significant trees on the subject property excepting only those lands where existing vegetation would not be disturbed in any manner including, but not limited to, lands covered by critical areas or critical area buffers. The tree retention plan shall be prepared by a qualified professional such as a licensed landscape architect, licensed/certified forester; licensed/certified arborist, or Washington State certified nurseryperson. The city may have submitted reports and tree retention plans peer-reviewed by qualified consultants at the applicant’s expense.
The tree retention plan shall include the following:
1. Location, size, species and driplines of all existing significant trees greater than eight inches in diameter measured four feet above grade;
2. Proposed and existing contours;
3. Trees and other vegetation to be retained and removed;
4. An evaluation by a qualified professional of all significant trees including those to be retained and removed;
5. A description of protection techniques to be utilized during construction to protect existing vegetation including, but not limited to, the use of an air shovel to locate the root zone, installation of a minimum four-foot-high chainlink or plastic-net fencing around tree driplines and/or root zones, using tunneling instead of trenching for utility installation, stump grinding instead of stump pulling and routing of construction traffic away from retained tree root areas to prevent soil compaction;
6. Tree retention plans shall indicate a disturbance-free area around all retained trees where the soil grade or ground contours shall not be altered. At a minimum, the disturbance-free area shall extend to a tree’s dripline or at least 15 feet from the trunk of a tree, whichever is the greater distance, unless an alternative tree protection method is submitted by a qualified professional, and said alternative method is approved by the city.
E. Significant trees shall be retained as follows:
1. Significant trees located within any required Type I or II perimeter landscape area as set forth in BMC 12.18.080(C) and 12.18.110 which do not pose a significant safety hazard as determined by a qualified professional.
2. Within the R 40,000, R 9,600, R 8,400, R 7,200, and R 5,400d zoning classifications, at least 20 percent of the total in diameter inches of the significant trees located within the net buildable area of the subject property as described within BMC 12.14.030 and 12.14.040 shall be retained.
3. Within all other zoning classifications, at least 20 percent of the total diameter inches of the significant trees located within the net buildable area of the subject property as described within BMC 12.14.030 and 12.14.040 shall be retained; provided, tree retention may be satisfied by retaining at least 15 percent of the tree diameter inches in significant trees and up to five percent of the tree diameter inches in existing trees two to eight inches in diameter or installing new coniferous trees at least six feet in height or new deciduous trees at least one and one-half inches in diameter. Each new tree installed shall be counted as two diameter inches toward the minimum required amount of tree diameter inches. For example, five new installed trees would be credited as 10 diameter inches.
4. Within the R-AC, DC, DN, DT, and GDC zones where the city desires to create compact, walkable neighborhoods, an applicant shall be required to preserve 15 percent of the site diameter inches of trees on the subject property but may implement the following alternative tree retention practices:
a. Retain existing coniferous or deciduous (excluding alders and cottonwoods) trees that are between two and eight inches in diameter as credit toward the 15 percent minimum site diameter inches retention; or
b. Install new coniferous and/or deciduous trees of an indigenous species to the maximum extent feasible on the subject property consistent with the following replacement ratios:
(i) Replace one significant tree with one new coniferous tree a minimum of 20 feet in height at time of planting; or
(ii) Replace one significant tree with two new coniferous trees a minimum of 14 feet in height at time of planting; or
(iii) Replace one significant tree with one new deciduous tree of a minimum diameter of four inches at time of planting; or
(iv) Replace one significant tree with two new deciduous trees of a minimum diameter of two inches at time of planting.
5. The selection of which existing significant trees are to be retained shall be based upon the following objectives:
a. Provide continuous overstory tree canopies;
b. Preserve trees in groupings or mutually supporting groves;
c. Protect trees adjacent to critical area buffers;
d. Retain or enhance the “feathered edge” visual effect of ridgeline trees against the sky. The feathered edge is more completely described within the Imagine Bothell… Comprehensive Plan Land Use Element and is depicted in Land Use Element Figure LU-5;
e. Retain those trees which a qualified professional has identified have the best chance of survival following development;
f. Retain trees which will be used as part of a low impact development storm water facility such as dispersion of surface water; and
g. Retain trees within an open space tract created as part of a clustered subdivision planned unit development pursuant to Chapter 12.30 BMC.
6. The community development director is authorized to allow the minimum percentage of retained diameter inches of existing significant trees on the subject property to be satisfied through the retention of existing trees (excluding alders and cottonwoods) that are two to eight inches in diameter and/or by installing new coniferous or deciduous trees of an indigenous species to the maximum extent feasible and meeting the minimum size provisions of BMC 12.18.140 only if, in consultation with the public works director, the community development director determines that retention of significant trees on the subject property is in conflict with the adopted infrastructure standards of the Bothell Municipal Code and the Bothell Design and Construction Standards. Trees that are two to eight inches in diameter that are proposed to be retained, consistent with this subsection, shall be identified, located, and evaluated pursuant to subsection D of this section.
7. The community development director is further authorized to require the applicant to implement minor site plan alterations to achieve the tree retention requirements identified within this chapter. In exercising the authority granted when implementing this requirement, the director shall avoid requiring site plan modifications that:
a. Require the relocation of a building or improvement more than 20 feet horizontally;
b. Affect the location of required sanitary sewer, water and other utility facilities;
c. Modify the construction and location of surface water facilities that are consistent with the Bothell Design and Construction Standards; and
d. Conflict with the location of access drives and streets as required by the Bothell Design and Construction Standards.
F. The community development director shall require a tree retention bond or other surety be submitted to the city of Bothell to ensure retention of existing trees and plant material during construction. In the event any trees designated by the city to be retained are removed, the city shall have the option of enforcing any bond posted. Each tree identified for retention shall be bonded pursuant to the following table. The applicant may request that the bond be waived for trees outside the project clearing area, such as those within critical areas and their buffers, and such requests shall not be reasonably denied.
8 – 12 inches
Larger than 12 – 16 inches
Larger than 16 – 20 inches
Larger than 20 – 24 inches
Larger than 24 – 28 inches
Larger than 28 inches
G. In the event that existing significant trees or vegetation which are designated to be retained die or are damaged or removed as a result of development activity, or which removal has been authorized by the city, prior to issuance of occupancy permits, or release of any tree retention bonds required pursuant to subsection F of this section, a restoration plan shall be prepared and submitted to the city for review and approval. The plan shall provide for replacement of trees in the following manner:
1. Each such significant tree designated to be retained that is removed or damaged as a result of development activity shall be replaced with new deciduous and/or coniferous trees pursuant to the following:
a. Replacement tree species shall be indigenous species to the maximum extent feasible or may be another species as approved by the city.
b. Replacement coniferous trees shall be as follows:
(i) Two trees for each significant tree removed with replacement trees being a minimum of 20 feet in height at time of planting; or
(ii) Four trees for each significant tree removed with replacement trees being a minimum of 14 feet in height at time of planting.
c. Replacement deciduous trees shall be as follows:
(i) Two trees for each significant tree removed with replacement trees being a minimum diameter of four inches at time of planting; or
(ii) Four trees for each significant tree removed with replacement trees being a minimum diameter of two and one-half inches at time of planting.
2. At the discretion of the community development director, the applicant may propose, and the director may allow, the retention of existing coniferous or deciduous (excluding alders and cottonwoods) trees that are between two and eight inches in diameter as credit toward the minimum site diameter inches retention standard, provided the coniferous or deciduous trees are identified, located, and evaluated pursuant to subsection D of this section.
3. Shrubs and ground cover shall be replaced by a mixture of Type VI indigenous materials in all disturbed areas.
4. Any funds generated by revocation of bonds for tree retention shall be used to plant new trees in the city of Bothell. (Ord. 2245 § 1, 2018; Ord. 2200 § 2 (Exh. B), 2016; Ord. 2087 § 2 (Exh. B), 2012; Ord. 1946 § 2, 2005; Ord. 1904 § 1, 2003; Ord. 1815 § 1, 2000; Ord. 1629 § 1, 1996).