HomeMy WebLinkAboutEx06_Updated_Arborist_ReportKennydale 320 Reservoir Arborist Notes
Urban Forestry Services, Inc.
April 2, 2018 Page 1 of 3
FIELD NOTES
SITE: Kennydale 320 Zone Reservoir Project
VISIT DATE: March 14, 2018
ATTENDING: Eric Ott, City of Renton; Marshall Meyer, MurraySmith
DATE: April 2, 2018
BY: Christina Pfeiffer
ISA Certified Arborist #PN-0124A,
ISA Tree Risk Assessment Qualified
Anna Heckman
ISA Board Certified Master Arborist #PN-6153B,
ISA Tree Risk Assessment Qualified
SCOPE: Review root zone protection and root pruning along the west side of the project area.
1. Site grading and tree root zone protection at the west side of the project area
Recent grading work stripped the sod and soil from the upper few inches of ground along
the west edge of the project site. There is a grove of mature conifers mixed with some smaller
deciduous trees on the adjacent property that are within proximity to the property line. Observing
these trees looking through the fence from the project site, we noted Douglas fir (Pseudotsuga
menzeisii), coast redwood (Sequoia sempervirens), Alaska yellow cedar (Chamaecyparis
nootkatensis), and green ash (Fraxinus pennsylvanica). From this one-sided view, all the trees
appear to be in good health. At least four of the conifers appear to be at least 30-inches in diameter.
This group of mature trees provides significant screening benefits. Within the recently graded area,
we observed some damage and severing of roots 2-inches or more in diameter that originate from
the trees on the adjacent property.
Recommendations
Provide Critical Root Zone (CRZ) protection for the large trees on the adjacent property to the west:
Protection of the ground over an area extending 25-feet east from the fence should provide
adequate CRZ protection for the larger diameter coast redwood trees located on the adjacent
property (Photo 1, Figure 1.
No further grading or significant grade changes should occur within this zone.
EXHIBIT 6
DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E
Kennydale 320 Reservoir Arborist Notes
Urban Forestry Services, Inc.
April 2, 2018 Page 2 of 3
Photo 1. Mature trees on the adjacent
property provide significant screening. View
is looking west. The circle indicates the
general area for the 25-foot wide CRZ area to
protect for these trees.
Photo 2. Cleanly prune damaged ends of
severed roots larger than 2-inch diameter.
Photo 2. Make clean cuts to repair damaged
ends of roots over 2-inches in diameter.
Utilize construction options to build up
from the existing grade to install new
pavement, keeping the base grade layer
shallow (IE: up to 4-inches gravel).
Do not excavate into the existing
grade.
Utilize trenchless construction, such as
boring, hand digging, or the careful use
of an air spade, for the installation of
underground utilities that pass through
the CRZ area where large diameter
roots are present. The goal is to keep
the larger diameter roots and their bark
covering intact.
Root pruning should be conducted to
make clean cuts to any severed roots
that are 2-inches or greater in diameter
to promote replacement growth (Photo
2). Immediately cover the pruned roots
with existing soil from the site.
Any areas within the CRZ area that
will not be paved should be covered
with a 4-inch depth of arborist wood
chip mulch (or material that meets the
WSDOT wood chip mulch
specification).
Provisions for supplemental irrigation
may be needed over this next summer
in event of prolonged drought or heat
conditions.
2. Considerations for the walnut tree near the reservoir tower construction.
This tree has been identified for removal due to its proximity to the limits of construction.
There has been some community interest in the potential to preserve this tree. During our field
meeting, we discussed potential options for minor adjustments that may improve the potential for
retaining this tree. Due to the placement of the construction fencing, we were only able to view one
side of the tree. From the previous UFS, Inc. tree assessment done for this site in fall of 2017, this
tree was noted to have an old injury with basal decay behind the new wood that has grown around
it. As such, this specimen doesn't merit extensive efforts to retain. However, it may be reasonable
to consider retaining it if that does not result in extensive cost or effort, and with the understanding
of the tree's current defects.
DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E
Kennydale 320 Reservoir Arborist Notes
Urban Forestry Services, Inc.
April 2, 2018 Page 3 of 3
Figure 1. The green outline indicates the approximate location of the trees on the adjacent
property. The red outline indicates the overall CRZ area to protect for the entire group of trees ,
extending 25-feet from the property line fence.
Walnut tree
4 Alaska yellow cedar
4 Coast redwood
2 Douglas fir
1 Green ash
DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E