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C ITY OF R ENTON T REE I NVENTORY R EPORT
Puget Sound Energy – Energize
Eastside Project
Prepared for:
Jens Nedrud
Puget Sound Energy
355 10th Avenue NE
Mail Stop: EST03W48
Bellevue, WA 98004
Prepared by:
May 2016
PSE 230kV Route Renton Tree Inventory Report
City of Renton Tree Inventory Report - II
The Watershed Company Reference Number:
111103.2
The Watershed Company Contact Person:
Jennifer Creveling, Senior Biologist
or Mike Foster, Ecologist & Arborist
Cite this document as:
The Watershed Company. May 2016. City of Renton Tree
Inventory Report: Puget Sound Energy – Energize Eastside
Project. Prepared for PSE.
The Watershed Company May 2016
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T ABLE OF C ONTENTS
Page #
1 Executive Summary............................................................................ 3
2 Introduction ......................................................................................... 4
2.1 Background ....................................................................................................... 4
2.2 Study Area ........................................................................................................ 4
3 Site Description .................................................................................. 5
4 Photos .................................................................................................. 8
5 Methods ............................................................................................. 11
5.1 Significant Trees ............................................................................................. 11
5.2 Non-Significant Trees and Shrubs ................................................................... 11
5.2.1 Landscaped trees and landscaped tall shrubs ............................................ 11
5.2.2 Weedy non-significant trees and tall shrubs; DBH between 3 and 6 inches 12
5.2.3 Weedy non-significant trees and tall shrubs; DBH less than 3 inches ...... 12
5.2.4 Hedges .............................................................................................................. 12
5.3 Authority .......................................................................................................... 12
5.4 Vegetation Mapping ........................................................................................ 12
5.5 Attribute data collection ................................................................................... 13
5.6 Data Management ........................................................................................... 15
5.6.1 Data Summary .................................................................................................. 15
6 Limitations of Study ......................................................................... 16
7 Tree Inventory Results ..................................................................... 17
8 References ........................................................................................ 19
PSE 230kV Route Renton Tree Inventory Report
City of Renton Tree Inventory Report - II
L IST OF F IGURES
Figure 1 - Map of proposed Oak and Willow routes from the Energize Eastside website. The Oak route is depicted in green while the Willow route variation is
shown in orange. ...................................................................................... 6
Figure 2 - Overview of the study area corridor in the City of Renton including the southern portion of Segment M (red) and Segment N (green). ................. 7
Figure 3 - A five-inch DBH apple tree tagged in Segment M in the City of Renton. (Photo
taken April 17, 2015) ................................................................................ 8
Figure 4 – A 0.75-inch caliper fruiting cherry tree that was recently installed in a
residential back yard in the City of Renton (#917). This tree, although small, has a maximum potential height of 25 feet. (Photo taken April 20, 2015) ........................................................................................................ 8
Figure 6 – A typical hedge of cherry laurel in Segment M in the City of Renton that was assessed and mapped as a polygon (polygon number p106). (photo taken April 20, 2015) ................................................................................ 9
Figure 7 – Segment N: The Cedar River Valley from the north rim looking south. (photo taken May 18, 2015) ................................................................................ 9
Figure 8 - Cedar Ridge Dr SE in Segment N with the existing transmission lines
overhead, looking east. (photo taken May 22, 2015) .............................. 10
Figure 9 - Larger trees growing in the Segment N easement on the north wall of the
Cedar River valley, looking south. (photo taken August 27, 2015) ......... 10
L IST OF T ABLES
Table 1 - Attributes recorded for all inventoried vegetation and that are presented in the
spreadsheet database. ........................................................................... 14
Table 2 – A list of species found in the City of Renton that were assumed to have been
planted. .................................................................................................. 15
Table 3 - Number of tagged and significant trees located on designated PSE segments in the City of Redmond. .......................................................................... 17
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Acronyms and Abbreviations
APS APS Survey & Mapping, LLC
DBH Diameter at 4.5 feet above the surface of the ground
ISA International Society of Arboriculture
PSE Puget Sound Energy
RMC Renton Municipal Code
ROE Right of entry
ROW Right-of-way
WSDOT Washington State Department of Transportation
TWC The Watershed Company
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The Watershed Company May 2016
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C ITY OF R ENTON T REE
I NVENTORY R EPORT
PUGET SOUND ENERGY – ENERGIZE E ASTSIDE
1 EXECUTIVE SUMMARY
The Watershed Company conducted a field-based tree inventory from March 23,
2015 to November 9, 2015, collecting data on a total of 6,166 trees and 357
groupings of small trees along the 18-mile-long Willow and Oak routes. Data
gathered from the study is included in the spreadsheet file that will be delivered
along with this and the other project reports. This inventory provides baseline
information and does not represent the number of trees that could be pruned or
removed as a result of the Energize Eastside project.
This report summarizes the portion of the route through the City of Renton. All
of Segment N and a portion of Segment M are located within the Renton City
limits. These Segments make up Phase 2 DEIS Segment 3. A total of 574 trees
were tagged and assessed in the City. Of those trees, 367 meet the City’s
definition of “significant tree”. Seven are large enough to be considered
“landmark trees”.
The study area is an approximately 100-foot wide easement where overhead
transmission lines currently exist. The subject lines in Segment N pass over a
large valley (Cedar River valley) where no inventory was conducted for several
hundred linear feet as no project work would need to occur in that area.
All vegetation with a potential to reach a height of 15 feet or more were
evaluated under this study. Any landscaped tree or shrub meeting this criteria,
regardless of trunk diameter or height, was marked with a small, numbered
aluminum tag with either a nail or wire tie. Clusters of small, non-significant
weedy trees were grouped in a polygon and assessed as a unit. Hedges were
mapped and assessed using the polygon method as well.
The tree totals reported here are an underestimate of the total number of trees
subject to the inventory criteria in the study areas. Trees located in parcels where
crews were refused entry were not tagged, assessed or located. Several parcels in
the City of Renton refused entry to the Watershed field crew. More detailed
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parcel data (including records of refusal) were collected and tracked by Enviro
Issues and PSE during the field work.
2 INTRODUCTION
This report summarizes the findings for the City of Renton portion of the Willow
and Oak routes. The purpose of this tree inventory is to quantify and
characterize all significant trees, as well as vegetation with the potential to reach
greater than 15 feet in height along the 18-mile-long subject corridor consisting of
the routes known as “Willow” and “Oak”. This inventory provides baseline
information and does not represent the number of trees that could be pruned or
removed as a result of the Energize Eastside project. These routes have been
identified by Puget Sound Energy (PSE) as part of the Energize Eastside project.
The overall project crosses through a total of five local jurisdictions, including
King County and the Cities of Bellevue, Redmond, Newcastle, and Renton.
Trees inventoried in other jurisdictions as part of this study are summarized in
separate reports. Data collected during the study is compiled in an Excel
spreadsheet.
2.1 Background
The Energize Eastside project proposes to build a new electric substation and
higher capacity transmission lines to serve homes and businesses on the Eastside.
Current route options include Oak and Willow routes that will extend from the
Sammamish substation in Redmond to the Talbot substation in Renton (Figure
1). The two routes diverge only though a portion of the City of Bellevue. Each
route option includes a set of Segments, as follows: The Oak route comprises
Segments A, C, E, G2, I, K2, M, and N. The Willow route comprises Segments A,
C, E, J, M, and N.
2.2 Study Area
The length of the study area corridor in the City of Renton is approximately 3.7
miles beginning south of May Creek at SE 95th Street and continuing south to the
Talbot Hill substation (Figure 2). A total of approximately 850 linear feet of the
route at the bottom of the Cedar River valley was excluded where the lines are
far above the valley floor. Pole structures are located on the north and south
edges of the valley; the study area extended past the structures at either edge of
the valley by several hundred feet. The study area is defined as follows: on the
south side of the Cedar River valley, survey limits included the area
approximately 425 feet north of the existing pole structure(s); and on the north
side of the ravine, survey limits included the area approximately 250 feet south
beyond the existing pole structure(s).
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The study area corridor is an approximately 100-foot-wide easement that
includes two existing sets of 115kV transmission lines. These sets, consisting of
three conductors (wires) each, are spaced approximately 50 feet apart on center;
H-frame pole structures carry each set of transmission lines. As the lines enter
the Talbot substation, the two sets diverge and become wider than 50 feet apart,
but only for a relatively short distance.
3 SITE DESCRIPTION
The study area corridor in the City of Renton is dominated by urban land uses.
The majority of the corridor passes through parcels zoned residential,
commercial, or industrial. Within the residential areas, the corridor passes
through distinct neighborhoods; from north to south, these include Glencoe,
Honey Creek Ridge, Sunset, Liberty Ridge, and Shadow Hawk. The largest patch
of remaining undeveloped land is located adjacent to the Cedar River and zoned
Resource Conservation (RC). The study area corridor in the City of Renton is
located in Township 23N, Range 05E, Sections 4, 9, 16, 20, and 21.
Most of Segment M is characterized by residential and commercial landscaping,
with a forested ravine (Honey Dew Creek) near the northern limit. Segment N is
mostly non-landscaped weedy or forested areas beneath the existing powerlines,
with a few roadways and parking areas also present. A few forested patches are
limited to topographically low regions near the Cedar River and Honey Dew
Creek.
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Figure 1 - Map of proposed Oak and Willow routes from the Energize Eastside website. The Oak route is
depicted in green while the Willow route variation is shown in orange.
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Figure 2 - Overview of the study area corridor in the City of Renton including the southern portion of
Segment M (red) and Segment N (green).
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4 PHOTOS
Figure 3 - A five-inch DBH apple tree tagged in Segment M in the City of Renton. (Photo taken April 17, 2015)
Figure 4 – A 0.75-inch caliper fruiting cherry tree that was recently installed in a residential back yard in the
City of Renton (#917). This tree, although small, has a maximum potential height of 25 feet. (Photo taken April 20, 2015)
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Figure 5 – A typical hedge of cherry laurel in Segment M in the City of Renton that was assessed and mapped as a polygon (polygon number p106). (photo taken April 20, 2015)
Figure 6 – Segment N: The Cedar River Valley from the north rim looking south. (photo taken May 18, 2015)
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Figure 7 - Cedar Ridge Dr SE in Segment N with the existing transmission lines overhead, looking east. (photo taken May 22, 2015)
Figure 8 - Larger trees growing in the Segment N easement on the north wall of the Cedar River valley,
looking south. (photo taken August 27, 2015)
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5 METHODS
Watershed Company ISA-certified arborists conducted a field-based inventory
from March 23, 2015, to November 9, 2015 using the methods detailed below.
Proposed methodology was developed, written and submitted to PSE in a
Technical Memorandum dated March 13, 2015 for review and approved prior to
field work. The methodology was developed to comprehensively identify,
describe (by collecting attribute data), and mark (i.e., flagging to assist survey in
locating subject trees), all vegetation greater than 15 feet tall, or that had the
potential to reach a mature height of 15 feet or taller. The following
methodology is based on the memorandum. Any deviation due to specific
conditions encountered during field work is noted and described below.
5.1 Significant Trees
The City of Renton defines a significant tree as a tree with a caliper of at least six
inches, or an alder or cottonwood tree with a caliper of at least eight inches.
Trees qualified as dangerous are not considered significant. Trees planted within
the most recent ten years also qualify as significant trees, regardless of the actual
caliper (RMC 4-11-200). A landmark tree is defined as a tree with a caliper of
thirty inches or greater (RMC 4-11-200).
Any tree with a diameter of six inches at four-and-a-half feet above the surface of
the ground (DBH) was tagged and included in the inventory. A round one-and-
one-quarter-inch-wide, numbered aluminum tag was affixed to the trunk of
significant trees using a two-and-one-quarter-inch long aluminum nail (Figure 3).
Where property owners would not allow nailing, a small wire tie was used to
affix the tag to a lateral branch or smaller shoot near the trunk (Figure 4). For a
majority of the tags, a length of pink- and black-stripped flagging was included
behind the tag to aid survey crews in visually locating the subject trees. Survey
crews removed the bright flagging once the tree was survey-located.
Aluminum tags are intended to remain on the tree in perpetuity; however, they
will eventually be consumed by the expanding radius of the tree trunk. Some
tags may have been removed by property owners after the inventory work was
completed.
5.2 Non-Significant Trees and Shrubs
Small, non-significant trees and shrubs with a potential maximum height of 15
feet or more (regardless of height during the study) were assessed and mapped
according to the following methods:
5.2.1 Landscaped trees and landscaped tall shrubs
Any landscaped or maintained tree or shrub with a potential maximum height of
over 15 feet in a landscaped bed or maintained yard, regardless of trunk
diameter or height at the time of the field work, was inventoried. A numbered
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aluminum tag was affixed to the trunk with a nail where possible. If the trunk
diameter was smaller than two inches, generally the aluminum tag was affixed to
the trunk or a branch near the trunk using a wire tie (Figure 4).
5.2.2 Weedy non-significant trees and tall shrubs; DBH between 3 and 6 inches
In residential areas, any weedy, non-significant tree or shrub exhibiting a trunk
diameter of between three and six inches, with a potential maximum height of
over 15 feet, was tagged similar to Section 4.2.1.
5.2.3 Weedy non-significant trees and tall shrubs; DBH less than 3 inches
Groups of weedy, non-significant trees and tall shrubs (i.e., from seed [not-
planted] and not maintained) composed of species with a potential maximum
height of greater than 15 feet, but with stem diameters smaller than three inches,
were mapped and recorded as a polygon instead of as several individual points.
Attribute data was averaged and recorded for the group of vegetation. These
polygons were not survey-located. No significant trees were inventoried using
this method. Attribute data was collected for each polygon per Section 5.5 below
and is included in the data table.
5.2.4 Hedges
Landscaped hedges were also described and mapped using polygons instead of
tagging the individual plants that make up the hedge (Figure 6). Maintained
contiguous groupings of trees and shrubs with a potential maximum height of
greater than 15 feet growing in a row as a hedge, regardless of the maintained
height, were assessed as a polygon. Attribute data was collected for each
polygon per Section 5.5 below and is included in the data table.
5.3 Authority
Online resources were referenced to determine the maximum potential height of
the various species of tree and shrub encountered in the subject area. For
landscape trees and shrubs (plants not native to Washington State), the Oregon
State University Department of Horticulture online landscape plant database
(Oregon State University, 2016) was referenced. Native trees and shrub
maximum heights were verified using the University of Washington WTU
herbarium website (University of Washington, 2016) and the USDA plant
database (United States Department of Agriculture, 2016). These resources were
used for both the scientific names and the common names for the spreadsheet
reporting.
5.4 Vegetation Mapping
APS Survey and Mapping, LLC (APS) survey-located all TWC-tagged
vegetation, except for a subset of non-significant trees in the Talbot area of
Segment N (see below). The Watershed Company provided hand-drawn
sketches of the tag locations to APS survey crews after every day or two days of
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tagging to assist in finding all subject tress. Generally, APS survey-located
tagged vegetation within three days following the TWC inventory.
Polygons maps for vegetation described in Sections 5.2.3 and 5.2.4 were hand -
drafted on aerial imagery in the field. The sketched polygon locations were
converted into AutoCAD in the office by The Watershed Company.
PSE- and City of Renton-owned parcels in Segment N
Many common hawthorn, beaked hazelnut and Cascara trees exhibiting trunk
diameters of between three and six inches punctuate the large parcels near the
Talbot substation. Some of these trees were tagged by TWC; however, none
were survey-located by APS. APS survey crews had passed through to collected
data (including six inch and larger tree locations) in this portion of Segment N
before the TWC inventory work. APS was not contracted to revisit this area to
pick up the small trees. Therefore, some trees with a diameter of between three
and six inches in Segment N appear in the Excel spreadsheet database, but are
not included in the survey.
5.5 Attribute data collection
The attributes collected during the field survey are described in Table 1 below.
The Microsoft Excel spreadsheet database contains the data collected for each
tree and polygon inventoried. General attributes documented for all inventoried
vegetation include the date of assessment, unique identification number of tree
or polygon, location (parcel number), and name of plant species. Physical
attributes include number of stems, stem diameter (DBH), height, canopy radius,
condition, and notes. For polygons, approximate number of individual trees or
large shrubs within a polygon was recorded instead of stem number, and other
physical attributes for vegetation within polygons were recorded as averages.
Diameter of all subject trees was measured at four-and-a-half feet above the
surface of the ground at the trunk (DBH) where possible; however, some stems
were measured differently due to size or branching structure. Very small trees
without a defined stem at four-and-a-half feet above the ground were measured
using the caliper-method, where the stem is measured at six inches above the
ground. For trees with major branching at or below four-and-a-half feet, the
smallest portion of the trunk below major branching was measured.
Methodology for measuring diameter of trees with major leans, on steep slopes,
and with multiple trunks or stems generally followed those outlined in the Guide
for Plant Appraisal (Gooding, et al., 2000).
Other attributes collected are listed and described below.
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Table 1 - Attributes recorded for all inventoried vegetation and that are presented in the spreadsheet database.
ATTRIBUTE DESCRIPTION OF ATTRIBUTE
DATE OF ASSESSMENT Date that the Watershed Company field crew tagged and assessed the tree or shrub.
ID NUMBER Unique number assigned to an assessed tree or polygon. This number corresponds to the tag number in the field or the polygon number on the
maps.
PARCEL NUMBER Parcel number(s) in which the subject tree or polygon is located. In some cases, the parcel number corresponds to the closest parcel if the tree is
in a City right-of-way.
SCIENTIFIC NAME Formal scientific name conforming to the International Code of Nomenclature.
COMMON NAME Name that is based on normal or common language of the Pacific Northwest.
DECIDUOUS/EVERGREEN Notes whether a tree is considered deciduous or evergreen.
STEMS Number of trunks or shoots that contribute significantly to the canopy.
DBH Diameter at Breast Height; or 4.5 feet from the ground surface. See Section 4.5 for variations.
DBH2 DBH of secondary and other minor stems.
HEIGHT Approximate distance from the ground surface at the trunk to the highest point of the subject tree as visually estimated. Average height for
polygons.
CANOPY RADIUS Measurement from the stem to the average drip line, or end of branches.
CONDITION Health rating of an assessed tree using a 5-tier system as follows: 1 – Excellent: No apparent problems with the tree. Form is exemplary for the species. 2 – Good: Few minor defects such as crossed branches, minor foliage die-back, minor trunk damage, or unbalance canopy. 3 – Fair: Several minor problems exist. 4 – Poor: Major defects visible such as significant trunk decay, codominant leaders with included bark, significant canopy die-back, major cracks in a stem or major limbs, and/or other structural problems. Topped trees are generally considered poor. 5 – Dead or dying: Tree is dead or is in a state of significant decline.
NOTES Additional comments relating to assessment of the tree or polygon unit.
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5.6 Data Management
Data were recorded in the field using paper field data sheets. Data were entered
into a Microsoft (MS) Excel spreadsheet in the office and subsequently reviewed,
corrected, and organized into a searchable database. The spreadsheet file will be
delivered along with this report.
Polygons were hand-drawn on maps in the field, manually entered into ArcGIS,
reviewed and corrected before being converted to AutoCAD. Polygon features
will be delivered with this report as a .dwg file.
5.6.1 Data Summary
Summary data reported in the Tree Inventory Results section below was derived
from querying the tree spreadsheet using Excel formulas. The City of Renton
definition of a “significant tree” was used to tally data from the spreadsheet.
Any tree other than red alder or black cottonwood, no matter the condition
rating, with a diameter of six inches or greater was tallied. Red alders and black
cottonwoods with a diameter of eight inches or greater were added to the tally.
Additionally, Renton considers any tree “planted within the most recent ten
years” significant. Stem size was used as a surrogate for time since planting. Only
tree species that were likely purchased and installed exhibiting a caliper of
between zero and three inches were considered “recently planted”. Any tree that
likely grew from seed – red alder, black cottonwood, common hawthorn, beaked
hazelnut, cascara, sour cherry or Douglas-fir – were excluded. Table 2 shows the
list of species encountered along the corridor through Renton that were
considered to have been installed in a manner consistent with the significant tree
definition.
Table 2 – A list of species found in the City of Renton that were assumed to have been planted.
Apple Leyland cypress
Apricot Mountain hemlock
Asian pear Oriental dogwood
Callery pear Pear
Cherry plum Plum
Colorado blue spruce Plum species
European filbert (red leaf) Redbud
Landscaped Fir Rocky Mountain maple
Flowering crabapple Star magnolia
Flowering dogwood Sugar Maple
Fruiting Cherry Sweet cherry
Ginkgo Vine maple
Japanese flowering cherry Weeping hemlock
Japanese maple Walnut
Japanese snowbell Western serviceberry
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6 Limitations of Study
The number of trees reported below is an under-representation of the total
number of subject trees along the City of Renton portion of the Willow and Oak
routes. TWC and APS were denied entry to a few residential parcels in the City
and were unable to identify, assess, map or tally the trees in those parcels. The
details of which parcels were not inventoried were collected and tracked by
EnviroIssues and PSE during the field work.
Tree identification was done using the identifiable vegetative characteristics
present at the time of the inventory. Some trees and shrubs may be
misidentified. Some trees and shrubs were unidentifiable, although most were
identified to genus and species, or to at least genus. Some taxa, such as the
“cherry” genus, contain many species and botanical varieties that were not
identifiable given the time limitation of the inventory. Where genus was known,
but species was not, the species was indicated with “sp.” in the spreadsheet. An
unknown cherry tree, for example, was indicated as “Prunus sp.” If an
uncommon tree was simply not identifiable (for lack of leaves or flowers), an
“unk.”, or “unknown” was entered into the name column of the spreadsheet and
any descriptor that would aid in identification was added to the notes field.
Some reported parcel numbers in the spreadsheet may not be correct; the survey
should be used as the authority. Trees and polygons located on the edge of
parcel boundaries were assigned a parcel number based on field observations.
However, fence lines sometimes do not exactly match parcel lines and the parcel
boundary overlay on aerial imagery used in the field was sometimes inaccurate.
Determining exact parcel boundary locations in the field was not always
possible. The survey should be referenced to verify the exact ownership and
location of any particular tree.
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7 TREE INVENTORY RESULTS
Within the City of Renton, 574 trees were tagged and assessed for the tree
inventory; 367 of these trees are significant under the City of Renton definition of
“significant tree” (Table 3).
A total of seven assessed trees would be considered “landmark” by the City of
Renton. At 38.4 inches in diameter, tree number 990 – A Deodar cedar - is the
largest. It, along with number 932 – a ‘Crimson King’ Norway maple with a 32.7-
inch diameter – are in a residential part of Segment M. Both are topped to
maintain height below the existing lines. The other five landmark trees (numbers
3298, 3317, 3321, 3323 and 3325) are located on the undeveloped, forested slopes
of Segment N in the Cedar River valley.
A total of 48 polygons containing smaller trees and shrubs were assessed and
mapped along the corridor. Three large polygons delineate large tracts of weedy
vegetation along most of the route in Segment N. Much of the area contains a
mix of Himalayan blackberry thicket with beaked hazelnut, cascara, bitter cherry,
red elderberry, red alder, common hawthorn, and vine maple saplings. The
vegetation captured in these large polygons ranges from 0.25 to three inches in
diameter and between 10 and 20 feet tall.
Table 2 - Number of tagged and significant trees located on designated PSE segments in the City
of Redmond.
SEGMENT NUMBER OF TAGGED TREES
NUMBER OF SIGNIFICANT1
TREES
LANDMARK2 TREES
NUMBER OF POLYGONS3
DESCRIBED
M4 406 254 2 45
N 168 113 5 3
REDMOND TOTAL 574 367 7 48
Many of the polygons in Segment M describe landscape hedges composed of
arborvitae, cherry laurel, and Fraser photinia (Figure 6). But some non-hedged
beaked hazelnut, black cottonwood, red alder and common hawthorn are also
captured.
1 According to RMC 4-11-200 Definitions T, The City of Renton defines a significant tree as a tree with a caliper of at least six inches, or an alder or
cottonwood tree with a caliper of at least eight inches. Trees qualified as dangerous are not considered significant. Trees planted within the most
recent ten years also qualify as significant trees, regardless of the actual caliper (RMC 4-11-200D)
2 A landmark tree is any healthy tree with a diameter of 30 inches or larger (RZC 21.78).
3 Does not indicate number of trees included in each polygon. See spreadsheet for more information.
4 Indicates partial Segments; only the portion of the Segment in the City of Renton is included in the tree total numbers
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Subject trees in the Honey Dew Creek ravine and possibly in other locations
along the route may be located in wetland or stream buffers. See the City of
Renton Critical Areas Delineation Report: Puget Sound Energy – Energize Eastside
Project for more information on the location of critical areas. (The Watershed
Company, 2016).
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8 REFERENCES
Allen, E. A., Morrison, D. J., & Wallis, G. W. (1996). Common Tree Diseases of British
Columbia. Victoria, British Columbia, Canada: Natural Resources Canada,
Canadian Forest Service.
City of Renton. (2016, February 1). Renton Municipal Code. Retrieved March 1, 2016, from
Code Publishing Co.: http://www.codepublishing.com/WA/Renton/
Dunster, J. A., Smiley, E. T., Matheny, N., & Lilly, S. (2013). Tree Risk Assessment.
Champaign, IL: International Society of Arboriculture.
Gooding, R. F., Ingram, J. B., Urban, J. R., Bloch, L. B., Steigerwaldt, W. M., Harris, R. W.,
& Allen, E. N. (2000). Guide for Plant Appraisal (9th ed.). (P. Currid, Ed.)
Champaign, IL: International Society of Arboriculture.
Matheny, N. P., & Clark, J. R. (1994). A Photographic Guide to the Evaluation of Hazard Tress
in Urban Areas. Pleasanton: HortScience, Inc.
Oregon State University. (2016, January 15). Landscape Plants: Images, Identification, and
Information. (P. Breen, Editor) Retrieved 2015, from Oregon State University
Horticulutre Department: http://oregonstate.edu/dept/ldplants/
The Watershed Company. (2016). City of Renton Critical Areas Delineation Report: Puget
Sound Energy – Energize Eastside Project. Prepared for PSE.
United States Department of Agriculture. (2016, January 15). Natural Resources
Conservation Service. Retrieved from PLANTS Database:
http://plants.usda.gov/java/
University of Washington. (2016, Januray 15). WTU Image Collection: Plants of Washington.
Retrieved 2015-2016, from Burke Museum of Natural History and Culture:
http://biology.burke.washington.edu/herbarium/imagecollection.php