APPROVED TRE RESUB 1+PLN2021-0021+Arborist Report+4.21.2022_12.08.35_PM+2818901Creative Landscape Solutions
19508 88th Ave W 1
April 13, 2022
Kayla Clark Nichols
Project Coordinator
Select Homes, Inc.
206.963.3365
Site: 19508 88th Ave W
Edmonds, WA 98029
TPN: 27041800303400 + 27041800303200
Size of area: .28 + .68 = .96 acres
Re: RFI dated February 25th, 2022, all changes highlighted in yellow
Dear Kayla:
Thank you for requesting my services. On January 3rd, 2022, we visited the site located above in
Edmonds, WA to perform a Level 2 Tree Risk Assessment (VTA) for all onsite trees as well as offsite
trees with driplines that extend over the site.
The applicant proposes to divide the site into three (3) SFR parcels; the lot on the east side will retain
the existing home.
In summary:
Tree Density Calculations
Total number of onsite trees 6
Total number of unhealthy trees 1
Total number of healthy trees 5
Total number of trees removed for site improvements 1
Number of trees required to be retained (6 * .3) 2
Total number of retained trees 4
% retention (4/6) >50% 66%
Total mitigation for removed trees 4
Tree Mitigation per Lot*
Lot 1 0
Lot 2 (14,970 sq ft/8000 = 1.87) + #259 3
Lot 3 (13,298 sq ft/8000=1.6 1
*ECDC 23.10.C.5
I have included a detailed report of my findings. If you have any questions, please call me. I can be
reached on my cell phone: 425.890.3808 or by email: sprince202@aol.com.
Warm regards,
Susan Prince
Creative Landscape Solutions
ISA Certified Arborist: PN #1418A
TRACE Certified Arborist: #418
17518 NE 119th Way
Redmond, WA 98052
Creative Landscape Solutions
19508 88th Ave W 2
* Per City of Edmonds 23.10.020(P) Significant Tree – A tree that is at least six (6) inches in diameter at breast
height (DBH) as measured at 4.5 feet from the ground. For trees with multiple leaders at four and one-half (4.5)
feet height, the DBH shall be the combined cumulative total of branches greater than six (6) inches diameter at
four and one-half (4.5) feet above the average grade. If a tree has been removed and only the stump remains that
is below four and one-half (4.5) feet tall, the size of the tree shall be the diameter of the top of the stump.
Creative Landscape Solutions
19508 88th Ave W 3
Personal qualifications, scope of work and methodology
My examination was limited to a visual one, and did not involve any root excavation, trunk or limb
coring, or any soil testing. To evaluate the trees and prepare the report, I drew on my formal college
education in botany, preparation and training used to obtain my ISA certification in addition to my
certification as a Tree Risk Assessor. I have worked in the field of arboriculture since 1996, have been
an ISA Certified Arborist for since 1999, and have been TRACE/TRAQ certified since 2009.
I followed protocol delineated by the International Society of Arboriculture (ISA) for Tree Risk
Assessment (TRA). By doing so, I am examining each tree independently as well as collectively as
groups or stands of trees provide stability and can lower risk of independent tree failure. This scientific
process examines tree health (e.g., size, vigor, insect, and disease process) as well as site conditions
(soil moisture and composition, the quantity of impervious surfaces surrounding the tree etc.)
Introduction:
Identifying and managing the risks associated with trees is still largely a subjective process. Since the
exact nature of tree failures remains largely unknown, our ability as scientists and arborists to predict
which trees will fail and in what fashion remains limited. As currently practiced, the science of hazard
tree evaluation involves examining a tree for structural defects, including genetic problems, those
caused by the local environmental that the tree grows in and those attributed to man (pruning etc.).
The assessment process involves evaluating three components: 1) a tree with the potential to fail, 2)
an environment that may contribute to that failure, and 3) a person or object that would be injured or
damaged (the target). A defective tree cannot be considered hazardous without the presence of a
target.
All trees have a finite lifespan though it is not pre-programmed internally in the same manner as
annual plantings. As trees age, they are less able to compartmentalize structural damage following
injury from insects, disease or pruning. Trees in urban settings have a shorter life span than trees
grown in an undisturbed habitat.
Each species and variety of tree grows differently. Evergreen trees have a “reputation” of growing
slowly and defensively. These trees allocate a high proportion of their resources to defending
themselves from pathogens, parasites, and wounds. As a rule, trees with this type of growth tend to
be long lived. Though like all other living things, they have a predictable life span. Examples of this
type of tree include the northwest Pseudotsuga menziesii - Douglas fir, and Thuja plicata - Western
red cedar.
Deciduous trees are trees that annually shed leaves or needles. These trees tend to grow quickly and
try to “outgrow” problems associated with insects, disease, and wounds. They allocate a relatively
small portion of their internal resources to defense and rely instead upon an ability to grow more
quickly than the pathogens which infect them. However, as these trees age, their growth rate
declines, and the normal problems associated with decay begins to catch up and compromise the
tree’s structural integrity. Examples of this type of tree include Salix, Populus and Alnus.
Knowledge of the growth and failure patterns of individual tree species is critical to effective hazard
analysis. Species vary widely in their rates of failure. The hazard tree evaluation rating system used
by most arborists was developed by the Colorado Urban Forest Council and recognizes this variation in
species failure and includes a species component as part of the overall hazard evaluation.
Creative Landscape Solutions
19508 88th Ave W 4
Methods used to determine tree location and tree health:
Trees were identified previously by numbered aluminum tags attached to the western side of the tree.
All the trees on site were examined using the Matheny and Clark1 criteria for determining the potential
hazard of trees in an urban environment as well as the Tree Risk Assessment in Urban Areas and The
Urban/Rural Interface by Julian Dunster2. Tree diameters were measured at DSH (diameter standard
height – 4.5’ above ground) using a logger’s tape. Tree driplines were measured using a PRO Laser
RangefinderTM.
Spreadsheet Legend:
1. Tree tag #: Numbered aluminum tags attached to the trees in the field*1
2. Species: The Latin and common name five a tree
3. Species: Species ID: Spreadsheet contains common names of trees which correspond to scientific
names as follows:
Apple: Malus sp.
American sycamore: Plantanus
occidentalis
Austrian pine: Pinus nigra
Bigleaf maple: Acer macrophyllum
Birch: Betula nigra
Bitter Cherry: Prunus emarginata
Blue atlas cedar: Cedrus atlantica
‘Glauca’
Cedar: Thuja plicata
Cherry: Prunus sp.
Dawn redwood: Chamaecyparis
nootkatensis
Deodora cedar: Cedrus deodara
Colorado blue spruce: Picea pungens
Cottonwood: Populus trichocarpa
Dogwood: Cornus nuttallii
Douglas fir: Pseudotsuga menziesii
English laurel: Prunus laurocerasus
Filbert: Corylus avellana var.
Grand fir: Abies grandis
Hemlock: Tsuga hetrophylla
Holly: Ilex aquifolium
Japanese maple: Acer palmatum
Leylandii cypress: Cupressocyparis
leylandii
Lodgepole pine: Pinus contorta
Mountain ash: Sorbus americana
Nobel fir: Abies procera
Pear: Pyrus sp.
Plum: Prunus
Red Alder: Alnus rubra
Red maple: Acer rubrum
Walnut: Juglans sp.
Western red cedar: Thuja plicata
Weeping Alaska cedar: Metasequoia
glyptostrobides
White fir: Abies concolor
White pine: Pinus strobus4
4. DBH: Diameter of the tree measured at 42” above grade
5. Adjusted Diameter of the tree: Calculated equivalent for multi-stemmed tree
6. Dripline Radius: Measurement in feet of the tree canopy from tree trunk to outermost branch tip
7.A. Windfirm: Whether the tree as a single retained tree has the trunk taper and buttress roots to
enable it to withstand strong gusts of
7.B. OK in Grove: the tree might not be windfirm as a stand-alone tree, however, it might be able to
be retained if it is located within a retained grove of 3+ trees with touching canopies.
8. Health: A measurement of overall tree vigor and vitality rated as excellent, good, and fair or poor
based on an assessment of crown density, leaf color and size, active callusing, shoot growth
rate, extent of crown dieback, cambium layer health, and tree age
Excellent: Tree is an ideal specimen for the species with no obvious flaws
Good: Tree has minimal structural or situational defects
OK: Tree has minimal structural defects AND minimal environmental concerns
Fair: Tree has structural or health issues that predispose it to failure if further stressed
Poor: Tree has significant structural and/or health issues. It is exempt from total tree count.
9. Defects/Concerns: A measure of the tree’s structural stability and failure potential and rated as
good, fair or poor based on assessment of specific structural features, e.g.., decay, conks, co-
dominant trunks, included bark, abnormal lean, one-sided canopy, history of failure, prior
construction impact, pruning history, etc.
10. Proposed action:
Retain
Remove due to viability
Remove due to planned development (tree is otherwise healthy)
Creative Landscape Solutions
19508 88th Ave W 5
11. Limits of disturbance: The area surrounding the tree that defines the area that surrounds the
trunk that cannot be encroached upon during construction. This may be a multiple of the trunk
diameter (1 -1.5 times the trunk diameter converted to feet.) or it may be related to the width
of the canopy. It is always determined by tree species and environment and is up to the
discretion of the ISA Certified Arborist to determine.
12. Tree Value: The measure of the tree by the municipality. Value maybe determined by the tree
DBH or it may be based on a table of corresponding tree credits, or it may be a % of the
number of trees on site. In Edmonds it is the tree count.
13. Mitigation for removed trees as determined by the Edmonds Municipal Code ECDC 23.10.080.A
Creative Landscape Solutions 19508 88th Ave W 6 Specific Offsite Tree Observations: 1 2 3 4 5 6 7 8 9 10 11 12 13 # Tree Tag # Species ID DBH (in) Adj. DBH (in) Drip-line radius (ft) Wind-firm OK in Grove Health Defects/Comments Proposed Action CRZ/TPZ/LOD Trees Healthy Trees Retained trees Mitigation* Re-tain Remove Radius in feet Viable Non-viable Remove site improvements N W E S 1 256 Golden chain 9,6,6,6,7 ** 34 15 OK Co-dominant leader with included bark X 5 @ root crown, vertical crack from root crown to 6' E, cavity @ -8' East, typical of species 1 15 15 15 15 1 1 1 2 257 Western red cedar 34 34 12 OK Thin canopy, typical of species 1 20 20 12 20 1 1 1 3 258 Ornamental plum 10, 4, 7** 21 14 Poor Co-dominant leader with included bark X 3@ root crown, decay throughout 1 14 14 14 14 1 4 259 Ornamental plum 8 8 17 OK Lean north, asymmetric canopy, north, cavity root crown to 7' 1 17 17 17 17 1 1 1 5 260 Maple 14,14** 28 15 OK Co-dominant leader with included bark X 2 @ root crown, moss and lichen, fused trunks, exposed roots, calloused wound @ 3' west, typical of species 1 15 15 15 15 1 1 1 6 261 Dogwood 10 10 10 OK Serpentine trunk, moss and lichen, poor pruning with decay, typical of species 1 10 10 10 10 1 1 1 *ECDC 23.10.080.A.1-3 6 4 1 1 6 5 4 1 **ECDE 23.10.020.R
Creative Landscape Solutions 19508 88th Ave W 7 Offsite Trees: 1 2 3 4/5 6 7 8 9 10 11 # Tree Tag # Species ID DBH inches * Drip-line radius feet Wind-firm OK in Grove Health Defects/Comments Proposed Action CRZ/TPZ/LOD Retain Radius in feet Viable Non- viable N W E S 1 A Douglas fir 32 14 OK Self-corrected lean to the east, previous top loss, elongated branch's, asymmetric canopy to north, typical of species 1 14 15 16 17 2 B Douglas fir 28 8 over property line OK Ivy root crown to 25', dead wood, broken branches, previous top loss, elongated branch's, kink@ 25' 1 8 over property line 8 over property line 8 over property line 8 over property line 3 C Douglas fir 32 8 over property line X Fair Moss and lichen, dead wood, broken branches, kink @ 50', previous top loss, elongated branch's, thin canopy 1 8 over property line 8 over property line 8 over property line 8 over property line 4 D Red alder 24 15 over property line X Fair Previous top loss, asymmetric canopy north, lean north' 1 15 over property line 15 over property line 15 over property line 15 over property line
Creative Landscape Solutions 19508 88th Ave W 8 1 2 3 4/5 6 7 8 9 10 11 # Tree Tag # Species ID DBH inches * Drip-line radius feet Wind-firm OK in Grove Health Defects/Comments Proposed Action CRZ/TPZ/LOD Retain Radius in feet Viable Non- viable N W E S 5 E Douglas fir 24 14; over property line OK Previous top loss, elongated branch's, typical of species 1 14; over property line 14; over property line 14; over property line 14; over property line 6 F Douglas fir 26 2' over fence OK Moss and lichen, typical of species 1 2' over fence 2' over fence 2' over fence 2' over fence 7 G Douglas fir 32 16' over fence OK Typical of species, fence built over buttress root 1 16' over fence 16' over fence 16' over fence 16' over fence 8 H Douglas fir 12 10 over fence OK Asymmetric canopy south, typical of species 1 10 over fence 10 over fence 10 over fence 10 over fence
Creative Landscape Solutions 19508 88th Ave W 9 1 2 3 4/5 6 7 8 9 10 11 # Tree Tag # Species ID DBH inches * Drip-line radius feet Wind-firm OK in Grove Health Defects/Comments Proposed Action CRZ/TPZ/LOD Retain Radius in feet Viable Non- viable N W E S 9 I Douglas fir 18 10 over fence OK Asymmetric canopy south, co-dominant leader with included bark X 2 reduced to 1 @ 8', asymmetric canopy south, typical of species 1 10 over fence 10 over fence 10 over fence 10 over fence * offsite DBH measurements are approximate
Creative Landscape Solutions
19508 88th Ave W 10
Aerial View:
Proposed Site Improvements: (For reference only; See Civil plans for specifics)
Creative Landscape Solutions
19508 88th Ave W 11
Discussion/Calculations/Conclusion:
Tree Density Calculations
Total number of onsite trees 6
Total number of unhealthy trees 1
Total number of healthy trees 5
Total number of trees removed for site improvements 1
Number of trees required to be retained (6 * .3) 2
Total number of retained trees 4
% retention (4/6) >50% 66%
Total mitigation for removed trees 4
Tree Mitigation per Lot*
Lot 1 0
Lot 2 (14,970 sq ft/8000 = 1.87) + #259 3
Lot 3 (13,298 sq ft/8000=1.6 1
*ECDC 23.10.C.5
The .96-acre site is currently accessed by a gravel drive located on the south side of the parcel. The
applicant proposed to divide the site into three (3) SFR lots; the existing home located on the east
side of the site will be retained.
There are six (6) onsite significant trees; one (1) is non-viable. Edmonds Municipal Code EMC
23.10.060.C1 requires 30% of the existing trees be retained, 6 * .3 = 2 trees should be retained.
The proposed improvements require the removal of tree # 259- 8” DBH Ornamental plum. The site
improvements allow for the retention of four (4) trees, exceeding required tree density by two (2)
trees.
Mitigation per ECDC 23.10.080.A.1-3 and ECDC 23.10.C.5 (mitigation to ensure that each 8,000 sq ft
has one (1) trees) in addition to mitigation for removed trees.
The location of that replacement tree will be provided during the building permit phase. ECDC
23.10.080.B.1 notes that no replacement is required for trees that are hazardous, dead, diseased,
injured, or in a declining condition with no reasonable assurance of regaining vigor.
Mitigations: Per ECDC 23.10.080.A (1-3)
A. Replacement required. Tree replacement is required for tree cutting permits required by
this chapter and/or for tree removal associated with the development types identified
in ECDC 23.10.060.A. Each significant tree to be removed shall be replaced as follows:
1. For each significant tree between 6 inches and 10 inches DBH removed, one (1)
replacement tree is required.
2. For each significant tree between 10.1 inches and 14 inches in DBH removed, two
(2) replacement trees are required.
3. For each significant tree greater than 14 inches in DBH removed, three (3)
replacement trees are required.
Creative Landscape Solutions
19508 88th Ave W 12
Replacement Specifications:
1. Minimum sizes for replacement trees shall be:
a. one-and-one-half-inch caliper for deciduous trees.
b. Six feet in height for evergreen trees.
2. The director may consider smaller-sized replacement trees if the applicant can demonstrate
that smaller trees are more suited to the species, the site conditions, and the purposes of
this section, and that such trees will be planted in sufficient quantities to meet the intent
of this section.
3. Replacement trees shall be primarily native species.
Appraisals:
No trees with DBH greater than 24” are proposed to be removed. No appraisals are necessary.
City comments and follow-up responses:
a. The tree protection fence locations shown on Sheets DM-01 and TR-01 indicate that retained Trees
#256, 260 and 261 will be partially fenced or that the fence will be moved during various development
stages, subjecting them to potentially damaging activities (such as the placement of materials) within
their designated limits of disturbance (LOD). Pursuant to ECDC 23.10.070.C and the conditions for
approval of the short plat, please show fencing on the subject property and in the right of way for
Trees #256, 260 and 261 consistently on Sheets DM-01 and TR-01, drawn to scale at the
recommended LOD, so that no access is permitted within the LOD and the fence is maintained in place
for the duration of the project. Completed by RAM Engineering
b. Although it appears adequate on DM-01, the tree protection fence for Offsite Trees A, B, C and D
does not appear to be shown at the applicant’s arborist recommended limits of disturbance on Sheets
TR-01 and TP-01. Further, the civil plans indicate these trees will be impacted by the proposed
construction of the stormwater drainage pump, catch basins and trenching for pipe, contrary to the
conditions for approval of the short plat and performance standards in ECDC 23.10.070. The City
strongly encourages the applicant to contact those neighbors about the proposed development and
potential impacts to those offsite trees. Completed by RAM Engineering (Catch basins moved outside
of the dripline of offsite trees.)
c. The arborist report indicates retained Tree #257 can be retained with a 12’ limits of disturbance,
while TR-01 and DM-01 show tree protection fence placed 10’ from the face of the tree trunk. The
proposed locations for road, utilities and storm drainage improvements on RS-01 and SW-01 indicate
it is highly unlikely that even a 10’ limit of disturbance can be observed during their installation.
Generally, a 30’ distance from the trunk would be considered the critical root zone adequate for a 32”
western red cedar, a species with a “poor-moderate” relative tolerance for root loss,1 particularly for a
cedar adjacent to roadway radiant heat. An LOD less than 20’ radius is unacceptable for Tree #257, as
excavating for the proposed civil improvements within 20’ would significantly reduce the chances of
the tree’s survival. Please indicate one from the following:
• Describe in the arborist report and on all plans listed by bullet on the 1st page, 2nd
paragraph how to successfully retain Tree #257 with adjustments to the locations of proposed
civil improvements outside a minimum 20’ LOD and/or tunneling utilities below roots per ECDC
23.10.070D.4. Revise the tree protection fence location and provide special instructions for
equipment operation adjacent to the 20’ LOD, specify that air excavations and root pruning at
the boundary of the 20’ LOD shall be done by a Certified Arborist and outline post-
development aftercare, OR
• Indicate the tree will be removed, adjust retention calculations, and submit the appraised
value of Tree #257.
Creative Landscape Solutions
19508 88th Ave W 13
Site utilities have been moved outside of the dripline of the trees and the Tree Protection Fencing
is shown at the requested 20’ radius.
Excavation and construction of the new access roadway should be supervised by an ISA certified,
Tree Risk Qualified arborist to ensure that the roots are properly cut to BMP and ISA standards. I
do not recommend air evacuation on the roots of this species. My anecdotal experience with this
technique on this species, is that the air dries the roots out and contributes to significant damage
to the fine roots of the tree.
Once the asphalt has be installed, please provide drip- irrigation to the dripline of the tree during
the months of July – September to encourage new root formation. I do not anticipate any issues
with the possibility of reflected heat from the asphalt damaging the tree at this distance.
2. Tree retention requirements. ECDC 23.10.060.C-E requires 30% of all significant trees in the
developable site be retained. According to the submitted plans, there are 5 significant trees
located on the subject property and 2 trees that appear to straddle the north property line,
Tree #260 and Offsite Tree G. Although ECDC 23.10 does not provide clear guidance for
shared tree retention and replacement requirements, each should be counted in a
consistent manner, rather than individually selected as on or off-site trees. In this case, each
boundary tree shall count as .5 (one half) tree and where applicable, the tree trunk size
(DBH) of boundary trees shall be divided in half. Establishing a consistent method for
counting tree retention is important for calculating tree replacements below. Please adjust
the calculations for tree retention and replacement shown in the arborist report and
Sheet L-1 accordingly.
There are a total of 6 trees on the short plat, having included Tree G and #260 as .5 each. A
minimum of 2 trees must be retained to meet the minimum 30% requirement. The
applicant has proposed to retain 4 trees, exceeding the minimum tree retention threshold.
If additional significant trees were to be removed with subsequent development phases
resulting in falling below the 30% threshold, the applicant must replace those trees
consistent with the requirements below. Corrected.
3. Tree replacement requirements. ECDC 23.10.060.4-5, ECDC 23.10.080 and the conditions for the
approval of the short plat require that:
• Every significant tree removed [except dead or poor condition trees] must be replaced,
depending on the size of the removed tree (ECDC 23.10.080). Note that the code under
Ordinance 4220 does not waive the fees in lieu of tree replacement if an applicant retains
50% of the existing significant trees on a development site. No tree replacement is required
for the removal of Tree #258 due to its condition. The replacement tree shown on Sheet L-1
within the setback on Lot 3 appears to be the required replacement for the removal of 8”
DBH Tree #259. Please adjust the tree retention and replacement calculations in the
arborist report and Sheets L-1 and TR-01 if the applicant cannot successfully retain Tree
#257. Delete any references to the 50% tree retention threshold. Indicate the tree will be
removed and submit the appraised value of Tree #257. N/A We have moved the utilities to
retain #257.
• For properties with less than 3 trees, at least 3 supplemental planted and/or retained
trees per 8,000 square feet is required. Please adjust the calculations in the arborist report
and on Sheet L-1 to reflect ECDC 23.10.060.C.5 requirements as follows: o Lot 1 - shows
Creative Landscape Solutions
19508 88th Ave W 14
the retention of 3.5 trees, Trees #256, 257, 260 (.5) and 261, exceeding the minimum 3
significant tree per lot requirement. If any trees on Lot 1 are removed, the minimum 3 tree
threshold is triggered so that supplemental trees would be required. In addition, the fee in
lieu requirements per ECDC 23.10.080.E.3 would apply if Tree #257 was removed, as it
exceeds 24” DBH. The removal of Tree #260, if it were removed, would not be subject to the
fee in lieu code provision as it is a shared tree and by dividing its DBH in half, is under the
24” threshold. Please adjust the arborist report and Sheet L-1 to show the number of
required tree replacements on Lot 1 if any trees are removed and submit the appraised
value of Tree #257 in the event it is removed. N/A We have moved the utilities to retain
#257.
o Lot 2 – has no significant trees, triggering the replacement requirements per ECDC 23.10
C.5 so that 2 trees must be planted (14,970 square feet/8,000 = 1.87, rounded up to 2 trees)
in addition to the 1 replacement tree required for the removal of Tree #259 (8” DBH = 1
tree) per ECDC 23.10.060.C.4. Please adjust the arborist report and Sheet L-1 accordingly
to show the required total of 3 new trees planted on Lot 2. Updated & complete
o Lot 3 has less than 3 significant trees, triggering the replacement requirements per ECDC
23.10 C.5 so that 1 new tree must be planted (13,298 square feet/8,000 = 1.6, rounded
down to 1.5 trees) since Tree G counts as .5 tree. Although its value is .5, 1 tree replacement
(but no fees in lieu) would be required if Tree G is removed. Please adjust the arborist
report and Sheet L-1 accordingly to show 1 new tree is required to be planted on Lot 3.
Updated & complete
Creative Landscape Solutions
19508 88th Ave W 15
Tree Protection Fencing: Tree Protection fencing should be erected prior to any site grading
First, protect roots that lie in the path of construction. Approximately 90 to 95 percent of a tree's root
system is in the top three feet of soil, and more than half is in the top one foot. Construction activities
should be avoided in this area. Protect as much of the area beyond the tree's dripline as possible.
Some healthy trees survive after losing half of their roots. However, other species are extremely
sensitive to root damage even outside the dripline.
Do not disturb the Critical Root Zone (CRZ). The CRZ is defined by its "critical root radius." Cde
requirements vary. In some municipalities the CRZ is the trees dripline, in other cities it is a function
of the DBH. To calculate critical root radius, measure the tree's diameter (DBH) in inches, 4.5 feet
above the ground. For each inch, allow for 1 to 1.5 feet of critical root radius. If a tree's DBH is ten
inches, its critical root radius is 10 to 15 feet. In practical field work, the arborist may extend or
reduce the trees CRZ measure based on site growing conditions, tree species, and tree shape for
example having an asymmetric canopy.
In addition to the CRZ, it is important to determine the Limits of Disturbance (LOD) for preserved
trees. Generally, this approximates the CRZ however in previously excavated areas around the dripline
the LOD may be smaller, or in the case of a tree situated on a slope the LOD may be larger. The
determination of LOD is also subject to the tree species. Some tree species do better than others after
root disturbance.
Tree protection is advised throughout the duration of any construction activities whenever the critical
root zone or leaf canopy many be encroached upon by such activities.
The Critical Root Zone (CRZ) or LOD should be protected with fencing adequate to hinder access to
people vehicles and equipment. Fencing detail is provided. It should consist of continuous 4 ft. high
temporary chain-link fencing with posts sec at 10’ on center or polyethylene laminar safety fencing or
similar. The fencing must contain fencing signage detailing that the tree protection area cannot be
trespassed on.
Soil compaction is one of the most common killers of urban trees. Stockpiled materials, heavy
machinery and excessive foot traffic damage soil structure and reduce soil pore space. The effected
tree roots suffocate. When construction takes place close to the protected CRZ, cover the site with 4
inches of bark to reduce soil compaction
Tree Protection fencing must be erected prior to soil excavation, boring, grading or fill operations. It
is erected at the LOD. If it is necessary to run utilities within the LOD, the utilities should be combined
into one cut, as practical. Trenching is not allowed in the LOD. In these areas, boring or tunneling
techniques should be used. If roots greater than 1” diameter near the LOD are damaged or torn, it is
necessary to hand trim them to a clean cut. Any roots that are exposed during construction should be
covered with soil as soon as possible.
During drought conditions, trees must be adequately watered. Site should be visited regularly by a
qualified ISA Certified Arborist to ensure the health of the trees. Tree protection fencing is the last
item to be removed from the site after construction is completed.
After construction, has been completed, evaluate the remaining trees. Look for signs and symptoms of
damage or stress. It may take several years for severe problems to appear.
If fencing around portions of the CRZ of a tree to be retained are not practical to erect due to
construction or obstacles, tree protection fencing should be placed three feet laterally from the
obstruction (ex. three feet back of a curb, building, or other existing or planned permanent
infrastructure.
Creative Landscape Solutions
19508 88th Ave W 16
Glossary:
ANSI A300: American National Standards Institute (ANSI) standards for tree care
Chlorotic: discoloration caused by lack of chlorophyll in the foliage
Conifer: A tree that bears cones and has evergreen needles or scales
Crown: the above ground portion of the tree comprised of branches and their foliage
Crown raise pruning: a pruning technique where the lower branches are removed, thus
raising the overall height of the crown from the ground
DBH or DSH: diameter at breast or standard height; the diameter of the trunk measured 54
inches (4.5 feet) above grade
Deciduous: tree or other plant that loses its leaves annually and remains leafless generally
during the cold season
Epicormic: arising from latent or adventitious buds
Evergreen: tree or plant that keeps its needles or leaves year-round; this means for more
than one growing season
Increment: the amount of new wood fiber added to a tree in a given period, normally one
year.
ISA: International Society of Arboriculture
Landscape function: the environmental, aesthetic, or architectural functions that a plant can
have
Lateral: secondary or subordinate branch
Limits of disturbance: The boundary of minimum protection around a tree, the area that
cannot be encroached upon without possible permanent damage to the tree. It is a
distance determined by a qualified professional and is based on the age of the tree,
its health, the tree species tolerance to disruption and the type of disturbance. It
also considers soil and environmental condition and previous impacts. It is unique to
each tree in its location.
Limited visual assessment: a visual assessment from a specified perspective such as foot,
vehicle, or aerial (airborne) patrol of an individual tree or a population of trees near
specified targets to identify specified conditions or obvious defects (ISA 2013)
Live crown ratio: the percentage of living tissue in the canopy versus the tree’s height. It is
a good indicator of overall tree health and the trees growing conditions. Trees with
less than a 30% Crown ratio often lack the necessary quantity of photosynthetic
material necessary to sustain the roots; consequently, the tree may exhibit low vigor
and poor health.
Monitoring: keeping a close watch; performing regular checks or inspections
Owner/manager: the person or entity responsible for tree management or the controlling
authority that regulates tree management
Creative Landscape Solutions
19508 88th Ave W 17
Pathogen: causal agent of disease
Phototropic growth: growth toward light source or stimulant
ROW: Right-of-way; generally referring to a tree that is located offsite on a city easement
Reaction wood: Specialized secondary xylem which develops in response to a lean or similar
mechanical stress, it serves to help restore the stem to a vertical position
Self-corrected lean: a tree whose trunk is at an angle to the grade but whose trunk and
canopy changes to become upright/vertical
Significant tree: a tree measuring a specific diameter determined by the municipality the
tree grows in. Some municipalities deem that only healthy trees can be significant,
other municipalities consider both healthy and unhealthy trees of a determined
diameter to be significant
Snag: a tree left partially standing for the primary purpose of providing habitat for wildlife
Soil structure: the size of particles and their arrangement; considers the soil, water, and air
space
Sounding: process of striking a tree with a mallet or other appropriate tool and listening for
tones that indicate dead bark, a thin layer of wood outside a cavity, or cracks in
wood
Structural defects: flaws, decay, or other faults in the trunk, branches, or root collar of a
tree, which may lead to failure; may be genetic, or environmental
Tree credit: A number assigned to a tree by a municipality that may be equal to the
diameter of the tree or a numerical count of the tree, or related to diameter by a
factor conveyed in a table of the municipal code
Trunk area: the cross-sectional area of the trunk based upon measurement at 54 inches
(4.5 ft.) above grade
Visual Tree Assessment (VTA): method of evaluating structural defects and stability in trees
by noting the pattern of growth. Developed by Claus Mattheck (Harris, et al 1999)
detailed visual inspection of a tree and surrounding site that may include the use of
simple tools. It requires that a tree risk assessor walk completely around the tree
trunk looking at the site, aboveground roots, trunk, and branches (ISA 2013)
Creative Landscape Solutions
19508 88th Ave W 18
References
Dirr, Michael A. Manual of Woody Landscape Plants, Their Identification, Ornamental
Characteristics, Culture, Propagation, and Uses. Champaign: Stipes Publishing
Company, 1990.
Dunster & Associates Environmental Consultants Ltd. Assessing Trees in Urban Areas and
the Urban-Rural Interface. US Release 1.0. Silverton: Pacific Northwest Chapter ISA,
2006.
Dunster, J. A. 2003. Preliminary Species Profiles for Tree Failure Assessment. Bowen Island:
Dunster & Associates Environmental Consultants Ltd.
Dunster, Julian A., E. Thomas Smiley, Nelda Matheny and Sharon Lilly. Tree Risk
Assessment Manual. Champaign, Illinois: International Society of Arboriculture,
2013.
Harris, Richard W, James Clark, and Nelda Matheny. Arboriculture, Integrated Management
of Landscape Trees, Shrubs, and Vines. 4th ed. Upper Saddle River: Prentice Hall,
2004.
Lilly, Sharon. Arborists’ Certification Study Guide. Champaign, IL: The International Society
of Arboriculture, 2001.
Matheny, Nelda and Clark, James R. A Photographic Guide to the Evaluation of
Hazard Trees in Urban Areas. Second Edition. Champaign, IL: The International
Society of Arboriculture, 1994.
Matheny, Nelda and Clark, James R. Trees and Development: A Technical Guide to
Preservation of Trees During Land Development. Champaign, IL: The
International Society of Arboriculture, 1998.
Mattheck, Claus and Breloer, Helge. The Body Language of Trees: A Handbook for Failure
Analysis. London: HMSO, 1994
Schwarze, Francis W.M.R. Diagnosis and Prognosis of the Development of Wood Decay in
Urban Trees. Australia: ENSPEC Pty Ltd. 2008
Sinclair, Wayne A., Lyon, Howard H., and Johnson, Warren T. Diseases of Trees and Shrubs.
Ithaca, New York: Cornell University Press, 1987.
Smiley, E. Thomas, Nelda Matheny, and Sharon Lilly, Tree Risk Assessment Best
Management Practices, ANSI A300 Part 9: Tree, Shrub, and Other Woody Plant
Management—Standard Practices (Tree Risk Assessment: Tree Structure
Assessment). The International Society of Arboriculture Press. Champaign. IL. 2011.
Thies, Walter G. and Sturrock, Rona N. Laminated root rot in Western North American.
United States Department of Agriculture. Pacific Northwest. Resource Bulletin PNW-
GTR-349. April 1995.
Creative Landscape Solutions
19508 88th Ave W 19
Assumptions and Limiting Conditions
1. Any legal description provided to the consultant/appraiser is assumed to be correct. Any titles
and ownerships to any property are assumed to be good and marketable. No responsibility is
assumed for matters legal in character. Any and all property is appraised or evaluated as thou
free and clear, under responsible ownership and competent management.
2. It is assumed that any property is not in violation of any applicable codes, ordinances, statutes
or other governmental regulations.
3. Care has been taken to obtain all information from reliable sources. All data has been verified
insofar as possible; however, the consultant/appraiser can neither guarantee nor be
responsible for the accuracy of information provided by others.
4. The consultant/appraiser shall not be required to give testimony or to attend court by reason
of the report unless subsequent contractual arrangements are made including payment of an
additional fee for such services as described in the fee schedule and contract of engagement.
5. Loss or alteration of any part of this report invalidates the entire report.
6. Possession of this report or a copy thereof does not imply right of publication or use for any
purpose by any other than the person to whom it is addressed, without the prior expressed
written or verbal consent of the consultant/appraiser.
7. Neither all nor any part of the contents of the report, nor copy thereof, shall be conveyed by
anyone, including the client to the public through advertising, public relations, news, sales or
other media, without the prior expressed written or verbal consent of the consultant/appraiser
– particularly as to value conclusions, identity of the consultant/appraiser, or any reference to
any professional society or instate or to any initialed designation conferred upon the
consultant/appraiser as stated in her qualification.
8. The report and any values expressed herein represent the opinion of the consultant/appraiser,
and the consultant’s/appraiser’s fee is in no way contingent upon the reporting of a specified
value, a stipulated result, the occurrence of subsequent event, nor upon any finding to be
reported.
9. Sketches, diagrams, graphs and photographs in this report, being intended as visual aid, are
not necessarily to scale and should not be construed as engineering or architectural reports or
survey.
10. Unless expressed otherwise: 1) information contained in this report covers only those items
that were examined and reflects the condition of those items at the time of inspection; and 2:
the inspection is limited to visual examination of accessible items without dissection,
excavation, probing or coring. There is not warranty or guarantee, expressed or implied, that
problems or deficiencies of the plants or property in question may not arise in the future.