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DEPARTMENT OF COMMUNITY CITY OF
AND ECONOMIC DEVELOPMENT Renton (D
TREE RETENTION WORKSHEET
Planning Division
1055 South Grady Way -Renton, WA 98057
Phone: 425-430-7200 I www.rentonwa.gov
1. Total number of trees over 6" diameter', or alder or cottonwood
trees at least 8" in diameter on project site 2 trees
2. Deductions: Certain trees are excluded from the retention calculation:
Trees that are dangerous2 trees
Trees in proposed public streets trees
Trees in proposed private access easements/tracts trees
Trees in critical area S3
and buffers trees
Total number of excluded trees:
0
trees
3. Subtract line 2 from line 1:
2
trees
4. Next, to determine the number of trees that must be retained 4, multiply
line 3 by:
0.3 in zones RC, R-1, R-4, R-6 or R-8
0.2 in all other residential zones
0.1 in all commercial and industrial zones
0
trees
5. List the number of 6" in diameter, or alder or cottonwood trees
over 8" in diameter that you are proposing5 to retain 4:
2
trees
6. Subtract line 5 from line 4 for trees to be replaced:
(if line 6 is zero or less, stop here. No replacement trees are required)
-1.8
trees
7. Multiply line 6 by 12" for number of required replacement inches:
-21.6
inches
8. Proposed size of trees to meet additional planting requirement:
(Minimum 2" caliper trees required for replacement, otherwise enter 0) inches per tree
9. Divide line 7 by line 8 for number of replacement trees6:
(If remainder is .5 or greater, round up to the next whole number) trees
1 Measured at 4.5' above grade.
Z A tree certified, in a written report, as dead, terminally diseased, damaged, or otherwise dangerous to persons or property by a licensed
landscape architect, or certified arborist, and approved by the City.
3 Critical areas, such as wetlands, streams, floodplains and protected slopes, are defined in RMC 4-3-050.
4 Count only those trees to be retained outside of critical areas and buffers.
5 The City may require modification of the tree retention plan to ensure retention of the maximum number of trees per RMC 4-4-1301-17a.
6 When the required number of protected trees cannot be retained, replacement trees, with at least a two-inch (2") caliper or an evergreen at least
six feet (6') tall, shall be planted. See RMC 4-4-130.H.1.e.(ii) for prohibited types of replacement trees.
1
H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Tree Retention Worksheet.docx 08/2015
Minimum Tree Density
A minimum tree density shall be maintained on each residentially zoned lot (exempting single-family
dwellings in R-10 and R-14). The tree density may consist of existing trees, replacement trees, or a
combination.
Detached single-family development': Two (2) significant tree S8 for every five thousand (5,000) sq. ft. of lot
area. For example, a lot with 9,600 square feet and a detached single-family house is required to have four (4)
significant trees or their equivalent in caliper inches (one or more trees with a combined diameter of 24"). This
is determined with the following formula:
Zol Areo
x 2 = Minimum Number of Trees
S, 000 s q. f t.
Multi -family development (attached dwellings): Four (4) significant trees8 for every five thousand (5,000) sq.
ft. of lot area.
Lot Are,
x 4 = Minimum Number of Trees
S,OOOsq,ft.
Example Tree Density Table:
Lot
Lot size
Min significant
New Trees
Retained Trees
Compliant
trees required
1
5,000
2
2 @ 2" caliper
0
Yes
2
10,000
4
0
1 tree (24 caliper
Yes
inches)
3
15,000
6
2 @ 2" caliper
1 Maple —15
Yes
caliper inches
1 Fir — 9 caliper
inches.
7 Lots developed with detached dwellings in the R-10 and R-14 zoned are exempt from maintaining a minimum number of significant trees onsite,
however they are not exempt from the annual tree removal limits.
8 Or the gross equivalent of caliper inches provided by one (1) or more trees.
H:\CED\Data\Forms-Templates\Self-Help Handouts\Planning\Tree Retention Worksheet.docx 08/2015