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Tree Report Page 1 of 6 King County South Treatment Plant
Tree Report
King County South Treatment Plant Biogas and Heat Systems Improvements
February 15, 2018
Prepared by: Mary Ellen Russell
Landscape Architect, Washington no. 1149, 2009
Tree Risk Assessment Qualification, International Society of Arboriculture, 2015
On November 15, 2017, I completed a level 1 (planning level) tree risk assessment for 180 existing trees
at the King County South Treatment Plant near impacts associated with proposed Biogas and Heat
System Improvements. This report details the results of those tree assessments. This report is written in
accordance with the requirements of Renton Municipal Code section 4‐4‐130, Tree Retention and Land
Clearing Regulations. Locations of assessed trees are shown on the Landscape and Tree Retention Plan.
A summary and details of the assessment are shown in the table below.
Of the 180 assessed trees, 42 trees with a Diameter at Breast Height (DBH) greater than 6” are proposed
for removal. 39 trees will be removed due to impacts of construction, 3 trees will be removed due to the
poor condition of the trees which makes their location near construction and proposed facilities high
risk.
All trees proposed to be retained will be protected with high visibility Tree Protection Fencing as shown
on the Landscape and Tree Retention Plans. Wherever possible, tree protection fencing shall be located
10’ from the base of the trunk or at the dripline, whichever is greater, to protect the critical root zone.
For trees to remain, no impacts shall be located closer than 5’ to be base of the trunk or in more than
25% of the critical root zone.
This project proposes to retain all trees for which the impacts of development will be minimal or none.
The tree retention priorities specified in RMC 4‐4‐130H.1.b have been considered as part of this report.
The assessed trees in this report do not include any Landmark (priority one) trees. The trees to be
retained consist of 138 priority two trees.
The existing assessed trees were planted as part of previous development projects with sufficient space
between them to allow development of even canopies. The proposed tree removals will likely not
impact the health or durability of existing trees to remain. The project proposes to retain 76% of the
existing significant trees on site. This is well above the minimum required threshold of 10% per RMC 4‐4‐
130H. No replacement trees are required.
7901 Woodlawn Ave NE, Ste 202
Seattle, WA 98115
206.898.6312
maryellen@russell‐lambert.com
Tree Report Page 2 of 6 King County South Treatment Plant
Tree Assessment Summary Table
Tree
No. Scientific Name
Common
Name Size Condition Condition Notes
Significant/
Landmark/
Dangerous
Remove/
Retain
Reason
for
Removal:
145 Fraxinus sp. Ash 12" 1 S Retain
146 Fraxinus sp. Ash 6" 1 S Retain
147 Pyrus calleryana Callery Pear 8" 3 Dead branches, lean D* Retain
150 Pinus nigra Black Pine 8" 1 S Retain
152 Fraxinus sp. Ash 8" 2 Broken limb S Retain
153 Pyrus calleryana Callery Pear 13" 2 Stunted S Retain
154 Pyrus calleryana Callery Pear 8" 1 S Retain
156 Pyrus calleryana Callery Pear 10" 1 S Retain
157 Calocedrus decurrens Incense Cedar 12' 1 S Retain
158 Calocedrus decurrens Incense Cedar 12" 1 S Retain
159 Calocedrus decurrens Incense Cedar 12" 1 S Retain
160 Calocedrus decurrens Incense Cedar 14" 1 S Retain
163 Pinus nigra Black Pine 8" 1 S Retain
164 Pinus nigra Black Pine 8" 1 S Retain
167 Pinus nigra Black Pine 8" 1 S Retain
168 Pinus nigra Black Pine 10" 1 S Retain
171 Pinus nigra Black Pine 6" 1 S Retain
173 Pinus nigra Black Pine 9" 2 Lean, corrected S Retain
174 Pinus nigra Black Pine 9" 1 S Retain
177 Fraxinus sp. Ash 7" 1 S Retain
179 Pinus nigra Black Pine 8" 1 S Retain
180 Pinus nigra Black Pine 9" 2 Thin canopy S Retain
181 Pinus nigra Black Pine 8" 2 Thin canopy S Retain
182 Pinus nigra Black Pine 10" 2 Thin canopy S Retain
183 Pinus nigra Black Pine 13" 2 Thin canopy S Retain
184 Pinus nigra Black Pine 8" 2 Thin canopy S Retain
185 Pyrus calleryana Callery Pear 6" 1 S Retain
187 Pinus nigra Black Pine 8" 1 S Retain
188 Liquidambar styraciflua Sweet Gum 6" 2 Dead branches S Retain
189 Pinus nigra Black Pine 12" 1 S Retain
190 Liquidambar styraciflua Sweet Gum 6" 1 S Retain
192 Pinus nigra Black Pine 7" 1 S Retain
194 Pinus nigra Black Pine 10" 1 S Retain
195 Pinus nigra Black Pine 7" 1 S Retain
196 Fraxinus sp. Ash 6" 1 S Retain
346 Malus sp. Crabapple 7" 3 Lean, stunted growth D Retain
349 Malus sp. Crabapple 8" 3 Severely stunted D Remove Condition
366 Calocedrus decurrens Incense Cedar 13" 1 S Retain
393 Pinus nigra Black Pine 12" 1 S Retain
406 Malus sp. Crabapple 8" 2 Response growth S Retain
408 Malus sp. Crabapple 6" 2 Response growth S Retain
Tree Report Page 3 of 6 King County South Treatment Plant
Tree
No. Scientific Name
Common
Name Size Condition Condition Notes
Significant/
Landmark/
Dangerous
Remove/
Retain
Reason
for
Removal:
412 Fraxinus sp. Ash 6" 1 S Retain
413 Fraxinus sp. Ash 6" 1 S Retain
415 Liquidambar styraciflua Sweet Gum 8" 1 S Remove Impacts
416 Fraxinus sp. Ash 13" 1 S Remove Impacts
419 Fraxinus sp. Ash 9" 1 S Retain
500 Populus nigra Cottonwood 10" 1 S Remove Impacts
501 Populus nigra Cottonwood 8" 1 S Remove Impacts
503 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
504 Fraxinus sp. Ash 7" 2 Broken branches S Retain
505 Pseudotsuga menziesii Douglas Fir 6" 1 S Retain
506 Pseudotsuga menziesii Douglas Fir 9" 1 S Retain
507 Pseudotsuga menziesii Douglas Fir 9" 1 S Retain
508 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
509 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
510 Pseudotsuga menziesii Douglas Fir 9" 1 S Remove Impacts
524 Pinus nigra Black Pine 8" 1 S Retain
525 Pinus nigra Black Pine 9" 2 Stunted S Retain
1405 Pseudotsuga menziesii Douglas Fir 7" 1 S Retain
1443 Picea abies Norway Spruce 16" 1 S Remove Impacts
1444 Picea abies Norway Spruce 11" 1 S Remove Impacts
1445 Picea abies Norway Spruce 16" 1 S Remove Impacts
1446 Picea abies Norway Spruce 14" 1 S Remove Impacts
1450 Picea abies Norway Spruce 10" 1 S Remove Impacts
1451 Picea abies Norway Spruce 8" 1 S Remove Impacts
1452 Picea abies Norway Spruce 17" 1 S Remove Impacts
1453 Pseudotsuga menziesii Douglas Fir 6" 1 S Remove Impacts
1455 Pseudotsuga menziesii Douglas Fir 7" 1 S Remove Impacts
1456 Picea abies Norway Spruce 8" 1 S Remove Impacts
1636 Malus sp. Crabapple 11" 2
Pruned limbs, response
growth S Remove Impacts
1637 Malus sp. Crabapple 10" 2
Pruned limbs, response
growth S Remove Impacts
1638 Malus sp. Crabapple 10" 2
Pruned limbs, response
growth S Remove Impacts
1639 Malus sp. Crabapple 8" 2
Pruned limbs, response
growth S Remove Impacts
1640 Malus sp. Crabapple 7" 2
Pruned limbs, response
growth S Remove Impacts
1641 Malus sp. Crabapple 7" 2
Pruned limbs, response
growth S Remove Impacts
1830 Prunus laurocerasus Laurel 13" 2 Pruned to shrub form S Retain
1831 Pinus nigra Pinus nigra 12" 1 S Retain
1832 Pinus nigra Pinus nigra 13" 1 S Retain
1862 Prunus laurocerasus Laurel 13" 2 Pruned to shrub form S Remove Impacts
1863 Prunus laurocerasus Laurel 14" 2 Pruned to shrub form S Retain
2038 Pinus nigra Pinus nigra 14" 1 S Retain
Tree Report Page 4 of 6 King County South Treatment Plant
Tree
No. Scientific Name
Common
Name Size Condition Condition Notes
Significant/
Landmark/
Dangerous
Remove/
Retain
Reason
for
Removal:
2039 Mystery Mystery 12" 1 S Retain
4230 Calocedrus decurrens Incense Cedar 7" 1 S Retain
4231 Fraxinus sp. Ash 6" 1 S Retain
4242 Fraxinus sp. Ash 7" 2 Response growth at base S Retain
4282 Fraxinus sp. Ash 7" 1 S Retain
4288 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4295 Fraxinus sp. Ash 6" 1 S Retain
4296 Fraxinus sp. Ash 7" 1 S Retain
4297 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4298 Pseudotsuga menziesii Douglas Fir 12" 1 S Remove
4388 Fraxinus sp. Ash 6" 1 S Retain
4389 Larix sp. Larch 6" 4 dead limbs, large cracks D Remove
4399 Larix sp. Larch 6" 4 dead limbs, large cracks D* Retain
4400 Pseudotsuga menziesii Douglas Fir 12" 1 S Remove
4401 Larix sp. Larch 6" 4 Mostly dead D* Retain
4409 Cretaegus x lavalleei Hawthorn 6" 2 Shrubby w/ root sprouts S Retain
4410 Cretaegus x lavalleei Hawthorn 6" 2 Shrubby w/ root sprouts S Retain
4411 Pseudotsuga menziesii Douglas Fir 11" 1 S Retain
4412 Pseudotsuga menziesii Douglas Fir 11" 1 S Retain
4413 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4414 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4415 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
4416 Pseudotsuga menziesii Douglas Fir 13" 1 S Retain
4417 Pseudotsuga menziesii Douglas Fir 13" 1 S Retain
4418 Pseudotsuga menziesii Douglas Fir 14" 1 S Retain
4419 Fraxinus sp. Ash 6" 2 Response growth at base S Retain
4420 Fraxinus sp. Ash 6" 1 S Retain
4632 Fraxinus sp. Ash 8" 1 S Retain
4633 Fraxinus sp. Ash 7" 1 S Retain
4635 Calocedrus decurrens Incense Cedar 8" 1 S Retain
4636 Calocedrus decurrens Incense Cedar 6" 1 S Retain
4637 Calocedrus decurrens Incense Cedar 10" 1 S Retain
4638 Fraxinus sp. Ash 11" 1 S Retain
4639 Pseudotsuga menziesii Douglas Fir 10" 1 S Retain
4857 Fraxinus sp. Ash 6" 2 Damage at base of trunk S Retain
4858 Fraxinus sp. Ash 7" 1 S Retain
4859 Fraxinus sp. Ash 6" 2 Damage at base of trunk S Retain
4860 Pseudotsuga menziesii Douglas Fir 7" 1 S Retain
4861 Pseudotsuga menziesii Douglas Fir 10" 1 S Retain
4862 Pseudotsuga menziesii Douglas Fir 10" 2 Missing leader S Remove
4863 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
4864 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
4893 Fraxinus sp. Ash 6" 1 S Retain
4894 Fraxinus sp. Ash 7" 1 S Remove
Tree Report Page 5 of 6 King County South Treatment Plant
Tree
No. Scientific Name
Common
Name Size Condition Condition Notes
Significant/
Landmark/
Dangerous
Remove/
Retain
Reason
for
Removal:
4897 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
4899 Pseudotsuga menziesii Douglas Fir 10" 1 S Remove
4900 Pseudotsuga menziesii Douglas Fir 10" 1 S Remove
4901 Pseudotsuga menziesii Douglas Fir 8" 1 S Remove
4947 Pyrus calleryana Callery Pear 6" 1 S Retain
5010 Calocedrus decurrens Incense Cedar 9" 1 S Remove
5011 Calocedrus decurrens Incense Cedar 11" 1 S Remove Impacts
5015 Pseudotsuga menziesii Douglas Fir 11" 1 S Remove
5016 Pseudotsuga menziesii Douglas Fir 9" 2 Topped S Remove Impacts
5059 Pseudotsuga menziesii Douglas Fir 14" 1 S Retain
5066 Pseudotsuga menziesii Douglas Fir 11" 1 S Retain
5067 Pseudotsuga menziesii Douglas Fir 12" 1 S Retain
5138 Calocedrus decurrens Incense Cedar 7" 1 S Retain
5140 Populus nigra Black Poplar 8" 1 S Retain
5161 Pseudotsuga menziesii Douglas Fir 7" 3 Severely broken leader D* Retain
5173 Calocedrus decurrens Incense Cedar 6" 1 S Remove
5232 Calocedrus decurrens Incense Cedar 11" 1 S Retain
5233 Calocedrus decurrens Incense Cedar 12" 1 S Retain
5234 Calocedrus decurrens Incense Cedar 12" 1 S Retain
*This tree is in decline. However, its location makes it unlikely to impact any target in the event of failure.
Therefore, despite its poor health, this tree may be retained with low risk. Trees in decline provide beneficial
habitat. If this area is impacted or improved, this tree should be removed.
Condition Key:
1) Excellent condition and vigor, no defects noted
2) Good condition and vigor, minor defects or signs of decay, but no significant risk
3) Fair condition and vigor, defects or signs of decay are present but do not pose significant risk
4) Poor condition and vigor, significant defects, significantly declining, dying, or dead tree
Limit of Liability
The terms and evaluation forms used in this report are as laid out in the International Society of
Arboriculture Tree Risk Assessment Manual, 2013.
There are many conditions affecting a tree’s health and stability which may be present and cannot
be ascertained, such as root rot, previous or unexposed construction damage, internal cracks, stem
rot and more. Changes in circumstances and conditions can also cause a rapid deterioration of a
tree’s health and stability. Adverse weather conditions can dramatically affect the health and safety
of a tree in a very short amount of time. While I have used every reasonable means to examine
Tree Report Page 6 of 6 King County South Treatment Plant
these trees, this evaluation represents my opinion of the tree health at the time of the evaluation
only. These findings do not guarantee future safety nor are they predictions of future events.
The tree evaluation is a Level 1 Assessment as defined by the International Society of Arboriculture.
It consists of a brief external visual inspection of an individual tree’s root flare, trunk, and canopy
from the ground only unless otherwise specified. As conditions change, it is the responsibility of the
property owners to schedule additional site visits by the necessary professionals to monitor the
long‐term health and risk of the tree.
This tree evaluation is to be used to inform and guide the property owner in the management of
their trees. This in no way implies that the evaluator is responsible for performing recommended
actions or using other methods or tools to further determine the extent of internal tree problems
without written authorization from the property owner. Furthermore, the evaluator in no way holds
that the recommendations are the only actions required to insure that the tree will not fail. Extreme
weather conditions can cause even low risk trees to fail.
A second opinion maybe sought if the client so desires. The client shall hold the evaluator harmless
for any and all injuries or damages incurred if the tree examined fails for any reason or if the
evaluator’s recommendations are not followed or for acts of nature beyond the evaluator’s
reasonable expectations, such as severe winds, excessive rains, heavy snow loads, etc.
If you have any further questions, please do not hesitate to call.
Sincerely,
Mary Ellen Russell, PLA
Principal, Russell + Lambert Landscape Architects
ISA Qualified Tree Risk Assessor