HomeMy WebLinkAboutTR_Cascade Crest_Arborist Report_260713_v1 Greenforest Incorporated
C o n s u l t i n g A r b o r i s t
greenforestinc@mindspring.com Tel. 206-723-0656
TO: Bob Wenzl
REFERENCE: Cascade Crest Regulated Tree Inventory Report
DATE: March 18, 2026
PREPARED BY: Favero Greenforest, ISA Certified Arborist # PN -0143A
ISA Tree Risk Assessment Qualified
ASCA Registered Consulting Arborist® #379
ASCA Tree & Plant Appraisal Qualified
You contacted me and contracted my services as a consulting arborist. My assignment is to
inspect trees at the above referenced site. The purpose of this report is to establish the
condition of the significant trees to satisfy City of Renton permit submittal requirements.
You provided me a topographic and boundary survey which I’ve attached to this report. I
visited the site last week and visually inspected the trees, which are the subject of this
report.
Summary
The following table summarizes the tree quantities and categories inventoried in this report.
Significant, Landmark and Dangerous categories are defined by municipal code.
Significant Trees on Site 11
Landmark Trees on Site 4
Dangerous Trees on Site 0
Total Subject Trees 15
Total Trees 15
Non-viable Trees 6
Total Viable Trees 9
Data for one (1) offsite tree is included in this report.
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 2 of 10
Greenforest Registered Consulting Arborist
Limitations and Use of this Report
This tree report establishes, via the most practical means available, the existing conditions
of the trees on the subject property. Ratings for health and structure, as well as any
recommendations are valid only through the development and construction process. This
report is based solely on what is readily visible and observable, without any invasive means.
There are several conditions that can affect a tree’s condition that may be pre-existing and
unable to be ascertained with a visual-only analysis. No attempt was made to determine the
presence of hidden or concealed conditions which may contribute to the risk or failure
potential of trees on the site. These conditions include root and stem (trunk) rot, internal
cracks, structural defects or construction damage to roots, which may be hidden beneath
the soil. Additionally, construction and post-construction circumstances can cause a
relatively rapid deterioration of a tree’s condition.
IDENTIFICATION SCHEME
Each tree was marked with a 1” x 3.5” aluminum tag indicating tree number as listed on the
attached inventory, and as shown on the attached exhibit.
SPECIES AND SIZE OF EACH TREE
I measured the trunk diameter (54” from grade) of each tree, and identified each tree by
common name.
TREE INSPECTION METHOD – TREE HEALTH, CONDITION AND VIABILITY
I visually inspected each tree from the ground. This is a limited visual assessment focuses on
identifying trees with imminent and/or probable likelihood of failure, and/or other visible
conditions that will affect tree retention.
I recorded tree species and size (DBH). I measured the average dripline of each tree. I rated
the condition of each tree, both health and structure. A tree’s structure is distinct from its
health. This inspection identifies what is visible with both.
High-risk trees can appear healthy in that they can have a dense, green canopy. This may
occur when there is sufficient sapwood or adventitious roots present to maintain tree
health, but inadequate strength for structural support.
Conversely, trees in poor health may or may not be structurally stable. For example, tree
decline due to root disease is likely to cause the tree to be structurally unstable, while
decline due to drought or insect attack may not.
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 3 of 10
Greenforest Registered Consulting Arborist
One way that tree health and structure are linked is that healthy trees are more capable of
compensating for structural defects. A healthy tree can develop adaptive growth that adds
strength to parts weakened by decay, cracks, and wounds.
This report identifies unhealthy trees based on existing health conditions and tree structure,
and specifies which trees are most suitable for preservation.1
No invasive procedures were performed on any trees. The results of this inspection are
based on what was visible at the time of the inspection.
The attached inventory summarizes my inspection results and provides the following
information for each tree:
Proposed Action is yet to be determined and will indicate if tree is to be removed or
retained.
Tree Category as defined by municipal code. RMC 4.11.200.Y. TREE: A woody
perennial usually having one dominant trunk, or, for certain species, a multi-
stemmed trunk system, with a potential minimum height of ten feet (10') at maturity.
Any trees listed on the complete King County Weed List shall not qualify as a tree.
1. Tree, High-Risk: Any tree that has been certified in a written arborist
report, prepared by an arborist with ISA Tree Risk Assessment
Qualification (TRAQ), as possessing the following ISA Tree Risk Assessment
characterizations:
a. The tree has a probable or imminent likelihood of failure; and
b. The tree has a medium or high likelihood of impact; and
c. The consequences of failure for the tree are significant or severe.
This level of risk assessment and reporting is outside the scope of this
assignment, and will also require site layout and identification of
specified targets (houses).
2. Tree, Landmark: A tree with a caliper of twenty four inches (24") or
greater, except for big leaf maples, black cottonwoods, and red alder
trees, which qualify as landmark trees with a caliper of thirty inches (30")
or greater.
1 Companion publication to the ANSI A300 Part 5: Tree Shrub and Other woody Plant Maintenance – Standard
Practices, Managing Trees During Construction. 2008. ISA.
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 4 of 10
Greenforest Registered Consulting Arborist
3. Tree, Protected: A significant tree identified to be retained, or a new tree
required to be planted, as a condition of approval for a land development
permit.
4. Tree, Significant: A tree with a caliper of at least six inches (6"), except
alder or cottonwood trees, which qualify as significant trees with a caliper
of eight inches (8") or greater. Trees certified as high-risk shall not be
considered significant.
5. Tree, Small Species: A tree with a mature height of thirty feet (30') or less.
6. Tree, Medium Species: A tree with a mature height between thirty feet
(30') and fifty feet (50').
7. Tree, Large Species: A tree with a mature height of fifty feet (50') or more.
Tree number as shown on tag in the field, and on attached exhibit.
DBH tree stem diameter in inches measured 4.5 feet from the ground. (Synonymous
with caliper as defined by municipal code; 4-11-030.C: A. CALIPER: The diameter
of any tree trunk as measured at a height of four and one-half feet (4-1/2') above
the ground on the upslope side of the tree.)
Tree Species Common name.
Dripline average branch extension from the trunk as radius in feet.
Health and Structure ratings ‘1’ indicates no visible health-related conditions or
structural defects, ‘2’ indicates minor visible problems or defects that may
require attention if the tree is retained, and ‘3’ indicates significant visible
problems or defects and tree removal is recommended.
Comments on Condition visible at time of inspection, which includes:
Asymmetric canopy – the tree has an asymmetric canopy from space and light
competition from adjacent trees.
Branch dieback - Mature branches in canopy are dying/dead.
Decay – process of wood degradation by microorganisms resulting in weak
and defective structure.
Diseased – foliage and trunk/stems are diseased.
Dogleg in trunk – trunk with a bow or defective bend (90°) in trunk often
halfway of further up the trunk.
Ivy - Dense ivy prevents a thorough inspection, and other defects may be
present.
Poor structure – tree’s structure is deformed and defective/unsightly
Thinning Canopy – low foliage density may indicate stress, or early
infection/declining health.
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 5 of 10
Greenforest Registered Consulting Arborist
Stump sprout- Tree previously cut at grade with multiple stems and
potentially weak attachments.
Suppressed – tree crowded by larger adjacent trees, with defective structure
and/or low vigor. Retain tree only as a grove tree, not stand-alone.
Topped – the tree is previously topped and has poor structure and/or stem
decay.
Tree suppressed - Tree is suppressed by adjacent tree canopies.
Trunk decay - Wood decay is visible in the trunk.
Wound/decay base of trunk - Open wound with visible decay in trunk.
Viability - a determination by the arborist whether the tree is viable for retention.
This is based on the tree’s likelihood of surviving for more than 5 years from
this assessment, based on current condition and anticipated impacts of site
development. This is not a risk assessment.
Retention Priority Criteria – indicates if tree is Landmark, >60’ tall, part of a
continuous canopy, >18” DBH, or is non-native.
Tree Type indicates if tree is Deciduous (D), Evergreen (E), broadleaf (B) and
coniferous (C).
SUBJECT TREES
The site currently has three (3) single-family residences and some out buildings. The
landscape and trees are neglected and overgrown. The trees are a mix of ornamental and
native evergreen, deciduous and fruiting species.
Overall, the conifers are in better condition than the deciduous trees.
TREE PROTECTION AREA BASED ON INDUSTRY RESEARCH AND STANDARDS
For proposed building placement and other improvements that require
excavation/trenching, and to assist with establishing tree protection areas (TPA),
Attachment 3 lists minimum distances based on industry standards for soil disturbance
deeper than 8 inches below existing grade. They are listed as ‘limits of disturbance’ (LOD)
and represent the limit of proximity for excavation near and past the rootplate of a tree,
while preserving health and stability.
The TPA, based on this LOD model, is typically the shape of a square and is most effective
when used for perimeter trees. Frequently a portion of this area is offsite or covering a
parking area (where the soil and roots are protected by paving), and sometimes the tree is
not centered in this defined TPA.
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 6 of 10
Greenforest Registered Consulting Arborist
This model establishes minimum distances of soil
disturbance for a single side of the box-shaped TPA. This
allows for work and access closer to the tree on a single
side and expands the protected area an equivalent
distance on the opposite side of the tree. (See diagram
right.)
The LOD are calculated for all the trees (and for trees on
adjoining parcels with overhanging driplines). They are
listed in Attachment 3 as distance in feet from the trunk
for the side of the tree to be impacted by construction.
They are determined using rootplate2 and trunk
diameter,3,4 Tree Fund research,5 and ISA Best
Management Practices.6
Attachments:
1. Assumptions and Limiting Conditions
2. Certification of Performance
3. Significant Tree Inventory
4. Tree Retention Plan
5. Planting and Maintenance Specifications
2 Coder, Kim D. 2005. Tree Biomechanics Series. University of Georgia School of Forest Resources.
3 Smiley, E. Thomas, Ph. D. Assessing the Failure Potential of Tree Roots, Shade Tree Technical Report. Bartlett
Tree Research Laboratories.
4 Fite, Kelby and E. Thomas Smiley. 2009. Managing Trees During construction; Part Two. Arborist News. ISA.
5 Andrew R. Benson, Andrew Koeser, Justin Morgenroth. Responses Of Mature Roadside Trees To Root
Severance Treatments. 2019. Journal of Urban Forestry & Urban Greening.
6 Companion publication to the ANSI A300 Series, Part 5: Managing Trees During Construction. 2008. ISA.
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 7 of 10
Greenforest Registered Consulting Arborist
Attachment No. 1 - Assumptions & Limiting Conditions
1. A field examination of the site was made 3/14/26. My observations and conclusions
are as of that date.
2. Care has been taken to obtain all information from reliable sources. All data has
been verified insofar as possible; however, the consultant/arborist can neither
guarantee nor be responsible for the accuracy of information provided by others.
3. I am not a qualified land surveyor. Reasonable care was used to match the trees
indicated on the sheets with those growing in the field.
4. Construction activities can significantly affect the condition of retained trees. All
retained trees should be inspected after construction is completed, and then
inspected regularly as part of routine maintenance.
5. Unless stated otherwise: 1) information contained in this report covers only those
trees that were examined and reflects the condition of those trees at the time of
inspection; and 2) the inspection is limited to visual examination of the subject trees
without dissection, excavation, probing, or coring. There is no warranty or
guarantee, expressed or implied that problems or deficiencies of the subject tree
may not arise in the future.
6. All trees possess the risk of failure. Trees can fail at any time, with or without
obvious defects, and with or without applied stress. A complete evaluation of the
potential for this (a) tree to fail requires excavation and examination of the base of
the subject tree. Permission of the current property owner must be obtained before
this work can be undertaken and the hazard evaluation completed.
7. The consultant/appraiser shall not be required to give testimony or to attend court
by reason of this report unless subsequent contractual arrangements are made.
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 8 of 10
Greenforest Registered Consulting Arborist
Attachment No. 2 - Certification of Performance
I, Favero Greenforest, certify that:
• I have personally inspected the trees and the property referred to in this report and
have stated my findings accurately.
• I have no current or prospective interest in the vegetation or the property that is the
subject of this report and have no personal interest or bias with respect to the parties
involved.
• The analysis, opinion, and conclusions stated herein are my own and are based on
current scientific procedures and facts.
• My analysis, opinion, and conclusions were developed and this report has been
prepared according to commonly accepted arboricultural practices.
• No one provided significant professional assistance to me, except as indicated within
the report.
• My compensation is not contingent upon the reporting of a predetermined
conclusion that favors the cause of the client of any other party nor upon the results
of the assessment, the attainment of stipulated results, or the occurrence of any
subsequent events.
I further certify that I am a member in good standing of International Society of
Arboriculture (ISA), and the ISA PNW Chapter, I am an ISA Certified Arborist (#PN-0143A) and
Tree Risk Assessment Qualified; a Registered Consulting Arborist® (#379) with American
Society of Consulting Arborists, and Tree and Plant Appraisal Qualified. I have worked as an
independent consulting arborist since 1989.
Signed:
GREENFOREST, Inc.
By Favero Greenforest, M. S.
Date: March 18, 2026
Favero Greenforest Digitally signed by Favero Greenforest
Date: 2026.03.18 12:06:32 -07'00'
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 9 of 10
Greenforest Registered Consulting Arborist
Dripline radius from center of tree
Condition ratings ‘1’ good to excellent, ‘2’ fair, ‘3’ poor
*For offsite trees, driplines are reported as branch length overhanging the subject property as measured from an existing fence. DBH is estimated.
Attachment No. 3 Significant Tree Inventory
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SIG. 5 2 8184 11.5” English hawthorn 14’ 6’ 2 2 Topped, diseased Y BD
SIG. 6 2 8185 14” English hawthorn 14’ 7’ 2 2 Topped, diseased Y BD
SIG. 0 2 8239 14” Black pine 10’ 7’ 1 3 Asymmetric canopy,
suppressed, curved trunk N CE
LAND. 9 1 8240 24” Blue spruce 14’ 11’ 1 1 Y CE
SIG. 7 2 8241 16” Blue spruce 12’ 8’ 1 1 Y CE
SIG. 4 2 8242 6.5” Moss cypress 7’ 5’ 2 2 Thin foliage, dogleg in trunk Y CE
LAND. 9 3 8243 24” Black cottonwood 14’ 11’ 1 2 Ivy covering trunk Y BD
LAND. 13 1 8259 54” Douglas-fir 38’ 18’ 1 1 Y CE
SIG. 4 2 8275 9.5” European birch 14’ 5’ 1 1 Y BD
Non-sig 0 8298 5” European birch 6’ 5’ BD
SIG. 0 2 8316 20” Bigleaf maple 15’ 10’ 3 3 Asymmetric canopy,
suppressed, curved trunk N BD
LAND. 13 1 8317 37” Douglas-fir 35’ 17’ 1 2 Dense ivy covering trunk Y CE
SIG. 0 2 8318 6,6,6” Bitter cherry 12’ 6’ 3 3 Stumpsprout N BD
SIG. 0 2 8319 10,11,12” Apple 22’ 7’ 3 3 Diseased, decay, decline N BD
SIG. 0 2 8320 15” Apple 18’ 7’ 2 3 Diseased, decay, decline N BD
SIG. 0 2 8321 10” Mt. Ash 15’ 5’ 2 3 Diseased, decay, decline N BD
OFFSITE LAND. 0 8342 26” Red maple 22’* 12’ Offsite BD
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NE 12TH STREET
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TPN: 092305-9135
FRANK YE
1161 OLYMPIA AVENUE NE
RENTON 98056
(PARCEL A)
TPN: 092305-9124
FRANK YE
3401 NE 12TH STREET
RENTON 98056
(PARCEL B)
SITE BENCHMARKEL=438.81
N88°00'28"W
105.08
8243
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82418242
8342
8321
8320 8319 8318
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8316
8259
8298
8275
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3401 NE 12th St 98056
1161 OLYMPIA AVE NE
Bob Wenzl
RE: Cascade Crest Regulated Tree Inventory Report
March 18, 2026
Page 10 of 10
Attachment No. 4 Tree Number Exhibit