Michael Bench, Peer Review of The Hills``- Michael L. Bench
Consulting Arborist
(831) 594-5151
�AW-1 ` l 7327 Langley Canyon Road
Prunedale, California 93907
A Peer Review of the Arborist Report
The Hills at Vallco Project
N. Wolfe Road and Stevens Creek Boulevard
Cupertino, California
Assignment
I was asked by Mr. Geoff Bradley, ACIP, Principal/President of M -Group and
Assistant to the Planning Department, City of Cupertino, to conduct a Peer Review
of the Arborist Report for The Hills at Vallco Project, Cupertino, California.
The Arborist Report was prepared by Mr. Walter Levison, ISA Certified Arborist
and ASCA Registered Consulting Arborist. Mr. Levison states that he reviewed
the exiting at this site in the Spring and Fall, 2015. Mr. Levison's Report is dated
10-5-15, Revised 10-30-15.
Observations
I inspected the trees at the site on November 16, 17, 2015.
I have worked with Mr. Levison on a few projects in previous years. I know Mr. Levison
to be a well qualified arborist, competent, and thorough. At the initiation of this review, I
had no reason to expect that Mr. Levison's work concerning this project was anything
less than competent and thorough. For this reason, I did not look at each tree
individually, and I did not take the time to review each tree with the detail prepared in
Levison's report. I looked at groups of trees primarily, except when an individual tree
would catch my eye. In those cases, I inspected those trees more closely.
This does not suggest that I agree with Mr. Levison concerning each tree. I found many
trees, in which I would rate their overall condition (health/structural integrity) slightly
lower than Levison.
Some trees have declined since Levison's report, despite the fact that the last revision
was 10-30-15. For example, Levison reported the coast redwood (Sequoia sempervirens)
Trees # 332, 333, 335, 501, 51, and 52 poor. These trees are now dead.
Prepared by Michael L. Bench, Site Observations:
Consulting Arborist November 16 &17, 2015
The Hills at Vallco
N. Wolfe Road
Cupertino, California
I observed the following trees to be dead, but it is possible that I may have over looked 2-
3. The current dead trees are: 17, 51, 52, 112, 113, 182, 203, 204, 209, 213, 218, 328,
332, 333, 335, 358, 479, 499, 500, 501, 502, 612, 659, 699, 700, 704, 709, 716, 718, 719,
812, 814, 815, 821, 827, and 1100. The majority of these are Coast Redwood (Sequoia
sempervirens), which should not be surprising. Although Sequoia sempervirens is the
State Tree, it is a very high water consumer. Most landscapes have cut back on water
usage. Some have turned off landscape irrigation. Thirsty trees, for example, Sequoia
sempervirens have declined or died in large numbers all over northern California. This is
expected to continue.
On this property, the single and double row of Sequoia sempervirens adjacent to the West
side property boundary are declining rapidly. I expect many more of these to be dead
within a year.
Most of the Sequoia sempervirens specimens near the buildings still have a fairly dense
canopies, but a close inspection suggests that these are all severely drought stressed. I
expect many of these to decline sharpely in the months ahead.
Another fairly high water consuming species, which was used extensively at this
property, is Shamel Ash (Fraxinus uhdei). The majority of the street trees (Trees # 8-50)
along Stevens Creek Boulevard and along N. Wolfe Road (Trees # 52-285 and Trees #
475-428) are Shamel Ash.. It appears that the irrigation has been maintained (perhaps
with minor reduction), because the majority of these trees are still in Fair to Good health.
However, it must be stated that the majority of these mature Shamel Ash are reaching the
end of their useful life. By this, they have grown to the point of using up most, if not all,
of their limited soil growing space. Once the roots stop growing, because they have
nowhere else to grow, the trees will start to decline. This is a slow process, but I expect
virtually all of the Shamel ash street trees to decline and die intermittently within a few
years ( 10-20 years estimated). Bear in mind, the Shame ash species is well known for
causing damage to sidewalks and infrastructure, especially as they mature.
The overwhelming majority of the trees in the interior of the site (parking areas
primarily) and the trees on the West and East boundaries are in decline and are in fair to
poor condition. This is in great part due to the reduction in irrigation, which is predicted
to continue. Experts are saying that California demand has exceeded supply and this
circumstance is not expected to change any time soon.
Prepared by Michael L. Bench, Site Observations: 2
Consulting Arborist November 16 &17, 2015
The Hills at Vallco
N. Wolfe Road
Cupertino, California
In my opinion, this is an opportunity to strategically and methodically remove the "thirsty
trees" a few at a time, and to replace them with low or very low water consuming
replacement trees and shrubs. Should this strategy be adopted for replacement,
unfortunately it would not be workable to remove "thirsty" trees intermittently in a group
of "thirsty" trees and to replant low water replacements. This would create an
incompatible planting. If you irrigate sufficiently to maintain the "thirsty" trees in those
areas, the low water consuming replacements would die from excess water. If you were
to suddenly change the irrigation to meet the needs of the low water consuming trees, the
"thirsty" trees would die. I would recommend that at new planting strategy of low water
consuming plants must be done be water zones. All of the trees and plants within those
zones must have similar needs. In places where this has been done successfully, it is
usually done on the basis of a 5 or 10 year plan, or longer.
Levison "recommends avoiding any transplants of existing trees at the Vallco site"
(P.24). I agree with this assessment. For example, the Holly oak (Quercus ilex) is in
excellent condition. It is one that could be considered for transplant, except for the fact
that specimens of the Quercus ilex species in recent years sometimes contract an disease,
which is a mystery and is unidentified by plant pathologists. Experts do not know what
the disease is and do not know what causes it. In my opinion, this makes a Holly oak,
even in excellent condition, a questionable candidate.
The plan proposes to remove and replace 115 trees. In light of my previous comments, I
think this number will be exceeded, not because of the proposed re -development, but
because of the fact that this property, like so many other properties, were planted at time
when it appeared that the supply of water would be plentiful. I suggest one of two
strategies to arrive at a more realistic number.
1. Use the Tree List provided by Levison. All, if not most of those trees, which
Levison has identified as having a health condition of 25% or less, I suspect will
not survive the construction period.
2. Strategically remove and replace trees essentially all of the "thirsty" specimens
with low water consuming specimens in planned areas that would coincide with
the redevelopment plan and schedule.
Respectfully submitted,
Michael L. Bench, Consulting Arborist
International Society of Arboriculture Certification # WE 1897A
American Society of Consulting Arborists Member
Prepared by Michael L. Bench, Site Observations: 3
Consulting Arborist November 16 &17, 2015