HomeMy WebLinkAboutTR_Arborist_Report_190426_v1
Renton Central Maintenance Facility
Tree Assessment
Date 1-11-2019
Department of Natural Resources and Parks
Parks and Recreation Division
King Street Center, KSC-NR-0700
201 S Jackson Street, Suite 700
Seattle, WA 98104
Table of Contents
1) Cover Sheet
2) Tabel Contents
3) Arborist Report
4) Arborist Report
Prepared for King County Parks & Recreation by:
Troy Deady
King County Parks
Certified Arborist PN-5972A
TRAQ Qualified
(206) 883 4206
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Arborist Report
The parcel of land #143000012 has 8 trees growing on it and 12 more outside the property line
to the North. With the exception of number 1, 2 and 3, the trees are viable, a low risk and should be for
several years.
Native Douglas Firs, number 11, 12, 13 and 18 are healthy, medium aged and size, have well-
established, live crowns of 75% or better. They are symmetrically weighted over sound root systems
and are growing outside the parcels North boundary fence. Current targets of impact are minimum and
the current risk rating is low.
Native Black Cottonwoods number 4 through 10 are small trees and currently grow on/near the
West and Northwest corner of the parcel. Black Cottonwoods number 14, 15 and 19 are larger trees
and grow outside the North boundary. Black Cottonwoods are a high risk tree when growing in an
environment where targets such as people, personnel property or the possibility for disruption of
activities exist. The level of risk usually increases as the trees grow in size or surroundings change. Black
Cottonwoods often begin life as volunteers. They begin life as a viable seed landing on the ground and
beginning to grow. This growth process may occur so easily that Cottonwoods are sometimes
considered a nuisance and/ or even an invasive tree species here in the Northwest. They are fast
growing and well adapted to the Pacific Northwest environment. Each Spring mature cottonwood trees
litter the ground with millions of seeds. Thousands of these seeds find suitable conditions to germinate,
and begin to grow. Some to become large and even gigantic trees in the years to come. Because of
how large they may become and the high likelihood of survival in most any environment, cottonwoods
are often growing in the wrong places. It is with this in mind that I have assessed the cottonwood trees
number 4, 5, 6, 7, 8, 9 and 10. Currently these healthy cottonwood trees are small and a low risk to the
electrical powerlines and the nearby structures but in a decade or so, that likely will change. Black
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Cottonwood number 14 is a root sprout but is a low risk of failure. In a decade it likely may be a high
risk and need to be removed. Both trees number 16 and 19 are large Black Cottonwood trees that are
healthy and vigorous. Each tree has a few negative structural characteristics however are currently
rated low risk.
Tree #20 is a native Big Leaf Maple. It has average health and vigorous growth. It is uncharacteristically
stout and wide spreading. It is growing on a small slope and has a north aspect. In the trunk where the
main structural branches attach there are several large wounds that should be monitored as the
environment and structure of the tree change with time. This tree is a candidate for end weight pruning
to decrease the branch load at the trunk.
All of the trees should be monitored by a certified Arborist on an annual basis during construction and
for several years thereafter, to ensure risk issues if present are promptly and properly mitigated.