HomeMy WebLinkAbout2/3/2026 Item 5g, Tway and Gault - Staff Agenda CorrespondenceCity of San Luis Obispo, Council Memorandum
City of San Luis Obispo
Council Agenda Correspondence
DATE: February 3, 2026
TO: Mayor and Council
FROM: Timmi Tway, Community Development Director
Prepared By: Walter Gault, City Arborist
SUBJECT: ITEM 5g - REVIEW OF A REQUEST TO REMOVE ONE TREE
ASSOCIATED WITH THE SLO REP THEATRE PROJECT LOCATED AT
614 MONTEREY STREET
Staff received the following questions regarding the request to remove one (1) 48 -inch
DBH Quercus agrifolia (Coast Live Oak) at 614 Monterey Street , with staff’s responses
shown in italics.
1) Why wasn’t the extent of the Oak’s root system disclosed earlier during the
design phase?
At the time this project was reviewed through the planning entitlement phase, an
arborist report was not required for projects. Previously, best practice considered
the canopy dripline to be the extent of a tree root system, and this is what was
shown on project plans. Current best practice states that the critical root zone
often extends well beyond the dripline. The City now requires an arborist report
with detailed information regarding root zones during the entitlement phase. The
project plans indicated the tree was to remain, and this was shown on the
building permit application. Once construction of the adjacent parking structure
began and detailed building plans for the SLO REP Theatre were submitted for
review, it became apparent that the roots occup ied a greater area than the
canopy dripline.
2) What is the age of the tree?
The arborist report, prepared by Rodney Thurman of Heritage Tree Arboricultural
Consulting, Inc., estimated that the tree age likely ranges from 65 to 96 years old.
To more accurately determine the age of trees, an increment borer would need to
be used to extract a small core sample to count growth rings.
Item 5g SLO Rep Theatre Tree Removal Request Page 2
3) Can the oak tree be transplanted?
An Oak tree of this size, age and structure would not be a candidate for a
successful transplant. Moving a tree of this size would be costly, logistically
difficult and would likely not result in the long term survival of the tree.
4) Is it possible to leave the tree in place to see if it survives, then replace
later if it does not?
Yes. The tree can remain and could be replaced later if it does not survive.
However, based on the tree’s known root structure and the existing and
proposed infrastructure required for the project, the likelihood of survival is low.
The consulting arborist determined that the tree would likely not survive unless
the project was redesigned to more appropriately accommodate the tree because
of the loss of canopy combined with impacts to the critical root zone. The
proposed theatre could be redesigned to reduce damage to the critical root zone.
This would be a fairly significant redesign that would require new architectural
and engineering plans, as well as additional review by the City. According to the
project representatives, this would result in a delay to the project schedule,
postpone the final completion and opening of the theatre, and could reduce the
size of the theatre to the extent that it no longer meets project objectives and
financial projections based on seating numbers and theatre offerings.
Item 5g SLO Rep Theatre Tree Removal Request Page 3
5) What is the estimated Diameter at Breast Height (DBH) and height for the
replacement tree in a 48-inch or 60-inch box?
Replacement trees in a 48-inch or 60-inch box are typically 8-10 feet tall with a
10-12 foot wide canopy. DBH at this size is not typically available from the
nursery as they are multi-trunk specimens (See Figure 1 below). Erythrina affra
(Mandela Coral tree) is expected to reach a height of at least 40 feet (See Figure
2).
Figure 1: 60-inch box Erythrina affra (Mandela Coral)
Item 5g SLO Rep Theatre Tree Removal Request Page 4
6) What is the estimated growth rate of the replacement tree?
Mandela Coral trees (Erythrina affra) grow quickly at an average of 3 feet of
growth each year.
7) Where are the replacement trees being planted and what species are
proposed to be planted?
The applicant is proposing to replant one (1) 60-inch box Mandela Coral
(Erythrina afra) tree onsite in the same area of the existing oak tree (see Figure
3) and four (4) 24-inch box trees from the Approved City Tree List off-site along
Nipomo Street (see Figure 4). Trees that have been considered for off-site
planting include Chitalpa x tashkentensis ‘Morning Cloud (see Figure 5) and
Cassia leptophylla (Gold Medallion) (Figure 6).
Figure 2: Large, mature specimen Erythrina affra
(Mandela Coral) tree located in a southern
California park
Item 5g SLO Rep Theatre Tree Removal Request Page 5
Figure 3: The dashed black line outlines the 20 foot x 20 foot area on the Landscape
Plan where SLO Rep proposes to replant one (1) 60-inch box Mandela Coral
(Erythrina afra) tree.
SLO REP Theatre
Figure 3: Four, 24-inch box trees from the Approved City
Tree List are proposed to be planted off-site along Nipomo
Street.
Item 5g SLO Rep Theatre Tree Removal Request Page 6
Figure 5: Chitalpa x tashkentensis ‘Morning Cloud
Figure 6: Cassia leptophylla (Gold Medallion)