Aborist Report TR-2020-022 Community Development Department
Planning Division — Cupertino
CUPERTINO Aff LIVED
May 27 2
Case# TR-2020-022 H O RT SCIENCE
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Dear Mr. Lindner:
You asked that I measure and evaluate additional trees on the Forum site that may need to be
removed for development; and you asked that I prepare a letter summarizing reasons for tree
removals. We met at the site on February 21, 2020 to review proposed development.
HortScience prepared an arborist report for the project in April 2017. In August 2017, we tagged
and assessed 48 additional trees. Eleven new trees were evaluated in February 2020 and
included the following:
• one London plane tree (#347) near the new skilled nursing facility(near tree#334);
• three Monterey pines (#349-351) and one Siberian (#348) elm along Via Esplendor,
south of the skilled nursing facility;
• and six London planes along Cristo Rey Dr. between Via Ventura and the entry circle
(#352-357).
The Tree Assessment (attached) includes the 11 new trees and an additional 7 trees (previously
tagged)that will be impacted by development. The Assessment includes tree disposition and
reasons for removal.
Based on plans, 14 trees will be impacted by construction and will need to be removed. Another
tree (Siberian elm #348) is recommended for removal because of its poor structural condition.
Transplanting
The City requested we explore the feasibility of relocating the London plane trees near the skilled
nursing facility along Cristo Rey(#331-334, 347), which need to be removed for road realignment.
When assessing whether trees can be successfully transplanted, we evaluate six criteria:
species, size, quality, accessibility to plants, new site characteristics, and cost relative to removal
and replacement. While trees of this species and in good condition respond well to transplanting,
the trees' sizes and existing site conditions make them difficult to relocate and reduce their
likelihood of survival.
However, the current planter size, location of existing road and curb, and proximity of trees to
each other limits the amount of soil and root volume that can be retained. A general guideline for
calculating root ball size is 10"for every trunk diameter inch. So for trunks ranging from 12-17
inches, the root balls would need to be 10-14 feet in diameter. Reducing the soil volume and
roots captured reduces a tree's ability to survive the transplanting process, and the London
planes, while tolerant of root loss, would likely decline post-transplanting.
Furthermore, London plane trees are cheap, fast-growing trees that are not considered "high
value" in the way native oaks are. Moving trees this size would cost thousands of dollars each.
For the same amount of money, many new young trees could be planted that will one day provide
more benefits than a few transplanted 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
Additional trees and removals HortScience I Bartlett Consulting
May 27 2020 Page 2
CommuntyDevelopment Department
P1;R)rt ras- ,M*nee WpordicMditions and available root volumes, I believe that transplanting
CUPERTINO these trex.pPmbacticable option.
Case# TreeVii. r r&Z2ecommendations
In oA00 idoiceduwErroot damage to Monterey pine#350 (in fair condition) I recommend the trash
enclosure be shifted away from tree#350 and closer to Siberian elm #348. Tree#349 is within
Approval Bod�4hCrepow( tf Iffenclosure location.
Approva I Date 06/25/20
Pmsei va a,, of additional frees ,s predicated on following the Tree Preservation Guidelines in the
Signature AlbehrALReport dated April 20, 2017.
Case Manager
Please contact me if you have any questions about my observations.
Sincerely,
4--'-�-�
Deanne Ecklund
ISA Certified Arborist WE9067-A
Registered Consulting Arborist#647
Attached: Tree Assessment
Tree Location Maps
HortScience I Bartlett Consulting • Divisions of The F.A. Bartlett Tree Expert Company
325 Ray St. Pleasanton, CA 925.484.0211 • www.hortscience.com