Updated Arborist Peer Review TR-2019-035, 3-24-2022 Community Development Department
Planning Division — Cupertino
CUPERTINO origARRWW. January 7, 2022
Case# t aM:1Iga"5?4, 2022
16Plication umber(s
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Approval Body: D%fbtJetnue BARTLETT CONSULTING
Approval Date ftQR4CA, 95014 u51-S of The FA Bartlett Tree ExPer[Company
Signature BriarOrJ(H [kousU _,_l_��e�w for Tree Removal Permit Application
Case Mana22890 Stonebridge Street(TR-2019-035), Cupertino, CA
Dear Brianne Harkousha:
The City of Cupertino requested that HortScience I Bartlett Consulting, Divisions of the F. A.
Bartlett Tree Expert Company, provide a peer review of the Tree Removal Permit Application
(dated January 14, 2021) submitted by the Cupertino Stonebridge Homeowners Association
(CSHOA). The application details CSHOA's request to remove and replace dead and
declining trees. To assist in my review, you provided Paul West's arborist report and letters,
photographs, and CSHOA's tree removal permit application forms. You asked that I address
three issues:
1. Is the recommendation to remove the trees supported by the facts?
2. Are the proposed replacement trees (species, location, and size) adequate?
3. Is the proposed irrigation method appropriate for the replacement trees and the site
conditions?
The following summarizes my observations and assessment.
March 24, 2022 Update:
As a follow-up to my January 7, 2022 analysis and recommendations on the following page, I
walked the site with Vern Dale (Cupertino Stonebridge Homeowners Association) on March
23, 2022. Based on my observations and conversations with Vern, I concluded the following:
1. The proposed planting locations are sufficient. The live oaks should be given as
much space as the site allows.
a. When the landscaping was installed for this HOA, large stature trees were
planted too densely and too close in proximity to structures (resulting in
suppressed trees with leans, low vigor, higher likelihood of failure, etc.). It is
very important that new trees are given adequate growing space.
2. The proposed removals of trees#11, 12, and 18 are justified due to a combination of
poor health, defective structure, and inadequate growing space.
3. The proposed removals of trees#2 and 3 are justified as they are in conflict with their
surroundings. The trees do not have enough growing space (they have low vigor
and leaning trunks as a result) and are in close proximity to an adjacent house and
fence. It is unlikely the trees will be an asset to the site in the future. They will
continue to decline and conflict with the structures nearby.
4. Vern informed me irrigation lines will be installed for all replacement trees.
HortScience I Bartlett Consulting . Divisions of The F.A. Bartlett Tree Expert Company
325 Ray St. Pleasanton, CA . 925.484.0211 . www.hortscience.com
Tree Removal Permit Peer Review HortScience I Bartlett Consulting
City of Cupertino—22890 Stonebridge, Cupertino Page 2
Community Development Department
Planning Division — Cupertino
CUPERTINO Jan �ANEDReport based on review of the removal application documents:
Case# TR-2019-035
e the trees supported by facts?
ihecapplicant s tree replanting spreadsheets list 18 trees for removal and replacement: 14
Approval I Body: D�� 'rl Winus halepensis), 2 magnolias (Magnolia sp.), and 2 purpleleaf plums (Prunus
ceraml e a ropurpurpea'). The trees were growing throughout the Stonebridge HOA and
Approva I Date "2b;Winspected by the applicant's arborist, Paul West. Mr. West recommended the
rernmKof the 18 trees due to death, poor health, or structural defects. According to Mr.
Signature Brian,ne_.ar,_o�sha _ _ ,._,_.,.�__
�,?s, LTle-Lreeswere-a„arnrrry-to-the association. Furthermore, no corrective actions could
be ta�Cen�to r�laintain the trees and eliminate the liability.
Analysis
Based on my review of the arborist report's photos and data tables, some of the tree removal
recommendations made by Mr. West appeared justified, while others were not.
• Aleppo pine#2 was recommended for removal because of codominant stems in its
crown. While codominant stems may be more weakly attached, that defect alone is
not sufficient justification for tree removal. The tree also had a lean, but it appeared
self-corrected.
• Aleppo pine#3 was recommended for removal because of a stem defect. However,
the defect(and its severity) was not visible in the photos provided.
• Aleppo pines#12 and 18 were recommended for removal due to leaning stems. The
presence of a lean does not necessarily mean a tree is unstable. Trees may
compensate for leans if they develop sufficient, stabilizing response growth. From
the photos provided, it was unclear to me whether this was the case. However, given
the history of whole tree (Aleppo pine)failures on the property, I think these
recommendations may be justified.
• The proposed removals of magnolias#5.1 and 5.2 appeared justified as the trees
had been topped.
• Of the 14 Aleppo pines listed for removal, 11 (#13-16 and 19-23)were removed in
October 2020. These removals appeared justified as the trees had already
experienced whole tree failure or were at high risk of failing.
• Of the two purpleleaf plums listed for removal (#11 and P), one (purpleleaf plum P)
was removed in October 2020. Its removal appeared justified as the tree had
exhibited signs of decline and root rot. Purpleleaf plum (#11)was documented as a
flowering pear in the arborist report. Its removal was recommended due a thinning
crown. From the photo, it was unclear what the extent of the crown thinning was.
Are the proposed replacement trees (species, location, and size) adequate?
Twenty-two (22)trees were proposed to replace the 18 trees to be removed/were previously
removed. Mr. West recommended planting small to medium trees due to the density of the
existing tree canopy. Proposed species included tristania, Bradford pear, olive, crape myrtle,
jacaranda, live oak, red maple, and river birch. Planting sizes were 24" box and 36" box.
Analysis
The proposed species are appropriate for the area with the exception of Bradford pear and
river birch. Bradford pear is an invasive species that is prone to limb failure. River birch is
not adapted to drought and climate change. It requires consistent and deep irrigation.
The applicant provided a replacement tree location map, but it lacked a scale. As a result, I
was not able to determine if the proposed trees were spaced appropriately. Crowns of
species such as live oak, olive, and jacaranda are often wider than tall and require more
growing space than species with narrow crowns. I recommend that the applicant revise their
HortScience I Bartlett Consulting • Divisions of The F.A. Bartlett Tree Expert Company
325 Ray St. Pleasanton, CA • 925.484.0211 • www.hortscience.com
Tree Removal Permit Peer Review HortScience I Bartlett Consulting
City of Cupertino—22890 Stonebridge, Cupertino Page 3
Community Development Department
Planning Division — Cupertino
CUPERTINO plan)WRIBlPMER-cale so that spacing can be evaluated. Trees planned in close proximity to
Case# 0ppap@tt@r-GLM as the pairs A& B, C & D, E & F, and U &V should be spaced at least 15'
p icaton um er s
same lines, trees A, G, H, J should be spaced at least 15'
away Trom adjacent buildings. Trees S and T (live oaks)were proposed in close proximity to
Approval I Body: D%ecOtPt�ta1 E lis species should be spaced no less than 40' apart.
Approva I Date *�207rWased numbers and sizes of replacement trees satisfied the City of Cupertino's
re I egnenthtree guidelines, which are based on replacing trees according to their trunk
Signature Briann Ear.ous a
Case Manager
Is the proposed irrigation method appropriate for the replacement trees and the site
conditions?
I cannot comment on this question. No irrigation plan was provided for my review.
Summary and Recommendations
To determine whether the proposed tree removals and replacement plan were sufficient, I
reviewed Paul West's arborist report and letters, photographs, and CSHOA's tree removal
permit application forms.
Based on my review of the reports and supporting documents, I concluded that the
application to remove trees#2, 3, and 11 was not adequately supported. Documentation to
confirm the stability of trees#12 and 18 was also lacking. In both cases, additional
documentation or a site visit would be required.
Furthermore, changes to the proposed species and planting locations should be made.
Lastly, to confirm the replacement trees will be adequately the maintained, the city should
review an irrigation and maintenance plan. Newly planted trees should be irrigated regularly
(usually weekly) during their establishment period (approximately 2 years).
Please contact me if you have any questions regarding my opinions.
Sincerely,
Jillian Keller, Consulting Arborist and Urban Forester
HortScience I Bartlett Consulting
Certified Arborist and Utility Specialist#WE-12057A
Tree Risk Assessment Qualified (TRAQ)
Wildlife Trained Arborist
HortScience I Bartlett Consulting • Divisions of The F.A. Bartlett Tree Expert Company
325 Ray St. Pleasanton, CA • 925.484.0211 • www.hortscience.com