HomeMy WebLinkAboutTR_Tree_Retention_Worksheet_20170419_v1DEPARTMENT OF COMMUNITY C;TY OF
Re nto1
AND ECONOMIC DEVELOPMENT
TREE RETENTION WORKSHEET
Planning Division
1055 South Grady Way -Renton, WA 98057
Phone: 425-430-7200 1 www.rentonwa.gov
I. Total number of trees over 6" diameter', or alder or cottonwood
trees at least 8" in diameter on project site 17 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 areas-' and buffers trees
1 Measured at 4.5' above grade.
z Atree 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.
d Count only those trees to be retained outside of critical areas and buffers.
s The City may require modification of the tree retention plan to ensure retention of the maximum number of trees per RMC 4-4-130H7a.
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 RMC4-4-130.H.1.e.(ii) for prohibited types of replacement trees.
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C:\Users\nkaba\AppData\Local\Temp\TreeRetentionWorksheet 701 sunset 10-30-16.docx Rev: 08/2015
Total number of excluded trees:
0
trees
3.
Subtract line 2 from line S:
17
trees
4.
Next, to determine the number of trees that must be retained', 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
5.1
trees
5.
List the number of 6" in diameter, or alder or cottonwood trees
over 8" in diameter that you are proposing' to retain 4:
5
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
trees
7.
Multiply line 6 by 12" for number of required replacement inches:
1.2
inches
8.
Proposed size of trees to meet additional planting requirement:
(Minimum 2" caliper trees required)
2.5
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)
n/a .48
trees
1 Measured at 4.5' above grade.
z Atree 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.
d Count only those trees to be retained outside of critical areas and buffers.
s The City may require modification of the tree retention plan to ensure retention of the maximum number of trees per RMC 4-4-130H7a.
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 RMC4-4-130.H.1.e.(ii) for prohibited types of replacement trees.
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C:\Users\nkaba\AppData\Local\Temp\TreeRetentionWorksheet 701 sunset 10-30-16.docx Rev: 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 trees" 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:
Lot Area x Z = Minimum Number of Trees
S 000 sq ft)
Multi -family development (attached dwellings): Four (4) significant trees' for every five thousand (5,000) sq.
ft. of lot area.
7 otArea
x 4 = Minimum Number of Trees
S, Ot30sq. f#.
14,400/5,000 = 2.85 X 4 = 11.52 Minimum Tree Density
Example Tree Densitv Table:
Lot
Lot size
Min significant
New Trees
Retained Trees
Compliant
trees required
1
5,000
2
2 @ 2" caliper
0
Yes
2
20,000
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.
Lot 1 Size 14,400 Min Significant Trees Required 5 New trees
g
Retained trees Yes
5 Cottonwood
49",20", 14", 10-
28" DBH's
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.
e Orthe gross equivalent of caliper inches provided by one (1) or more trees.
C:\Users\nkaba\AppData\Local\Temp\TreeRetentionWorksheet 701 sunset 10-30-16.ducx Rev: 08/2015