Title
Study session to facilitate community and Historical Advisory Board discussion of the Liquidambar (sweetgums) street trees along Gibbons Drive in the context of the Protected Trees section of Alameda Municipal Code Section 13-21.7 - Interim Review, the process for amending the list of protected trees, and the proposed Gibbons Drive Sidewalks and Trees Plan. This item is for discussion purposes only, and no approval or action is being taken at this time, and it is therefore not a project for purposes of the California Environmental Quality Act (CEQA). If future action is taken on the matters discussed in this report, the respective decision-making body will make the appropriate considerations under CEQA.
Body
To: Honorable Chair and Members of the Historical Advisory Board
From: Abby Thorne-Lyman, Interim Director of Planning, Building and Transportation
BACKGROUND
Certificate of Approval Process
Section 13-21 of the Alameda Municipal Code (AMC), Preservation of Historic and Cultural Resources, attached as Exhibit 1, establishes regulations intended to preserve and protect historical and cultural resources. AMC Section 13-21.5 outlines the Certificate of Approval process for alteration, demolition and removal of Historical and Cultural Monuments. Alameda has thirty (30) adopted Historical Monuments. In addition to Historical Monuments, AMC Section 13-21.7 - Interim Review specifies that certain structures, such as buildings constructed prior to 1942, and protected trees, are subject to the Certificate of Approval process prior to demolition or removal. Protected trees include Coastal Live Oaks anywhere in the City and certain trees in the public right of way (street trees) such as palm trees on Burbank Street and Portola Avenue, London Plane trees on Central Avenue, and median trees on Thompson Avenue (Christmas Tree Lane).
Tree Removal Policy and Planning Board Review
Gibbons Drive contains a mature canopy composed predominantly of Liquidambar trees (commonly known as sweetgums) planted within the planting strips between the sidewalk and roadway. The trees are a highly valued feature of the corridor and provide substantial canopy, shade, habitat, environmental benefits, and neighborhood character. As the trees have matured, however, their root systems have increasingly affected surrounding public infrastructure, including sidewalks, curbs and gutters, drainage facilities, curb ramps, water meter boxes, and underground streetlight electrical facilities. In several locations, displaced and uneven sidewalks pose pedestrian safety concerns and accessibility barriers, as defined in the Public Right-of-Way Accessibility Guidelines (PROWAG). Under Title II of the Americans with Disabilities Act (ADA), the City is responsible for providing accessible pedestrian facilities, including addressing accessibility barriers along public sidewalks. The Gibbons Drive Liquidambar trees are not listed as protected trees in AMC Section 13-21.7. Management of the Gibbons trees is governed by the City’s Master Street Tree Plan (2010) and the adopted Tree Removal Policy (Exhibit 2).
The City's Tree Removal Policy establishes the requirements and procedures for removing street trees throughout Alameda. The Policy recognizes the importance of preserving healthy trees and expressly prohibits their removal unless all practical alternatives have been considered. It provides a framework for evaluating conflicts between trees and public or private infrastructure while recognizing the importance of preserving the City's urban forest. It includes an arborist evaluation to ensure that the resolution of conflicts does not negatively impact tree health or unnecessarily create the risk of tree failure or future removal. The Tree Removal Policy also establishes separate provisions for dead, dying, or hazardous trees.
Of particular relevance to the Liquidambar trees on Gibbons Drive, Section D.1 of the Tree Removal Policy identifies specific site modifications to be evaluated before a healthy tree is removed. These include root pruning or shaving; modifying curbs while maintaining adequate drainage; reducing sidewalk width while meeting accessibility requirements; meandering or ramping sidewalks around tree roots; reducing curb width; providing curb breaks; and considering new technologies as they become available. These measures are intended to identify opportunities to resolve infrastructure conflicts while retaining existing trees.
When removal of a healthy tree is proposed, the Tree Removal Policy requires a report explaining the need for the proposed removal. The policy also establishes public notification, protest, and appeal procedures. For removals subject to Section D, these include posting notice on the tree, notifying adjacent property owners, providing information on the City's website, and allowing a 3-week opportunity for public protest before removal proceeds, including the opportunity to appeal the Public Works Director’s decision to the City Council.
In response to community and advisory body feedback and to provide greater consistency and transparency, the revised Gibbons Drive Sidewalks and Trees Plan (Plan), brought to City Council for consideration, will include a standardized Tree Preservation Evaluation form for locations where the removal of a healthy tree is proposed to make repairs needed for ADA compliance and other infrastructure needs. The public review version of the draft Plan is included as Exhibit 3.
The Tree Removal Policy also establishes additional review requirements for certain capital projects that propose removing more than 5% of the trees on a block face. While this requirement provides additional oversight of tree removals throughout the City, its application to Gibbons Drive presents a particular challenge because of the relatively small number of trees on each block face. Nine of the ten block faces along Gibbons Drive have between eight and 19 trees. On each of these block faces, removal of just one tree would exceed the 5% threshold. On the remaining block face, which contains 24 trees, removal of two trees would exceed the threshold. These counts include all existing street trees, not just Liquidambar. The Plan, therefore, includes an exemption from the 5% block-face review requirement for capital projects implemented in accordance with the adopted Plan. Since the Plan presents a coordinated, corridor-level approach that establishes a transparent decision-making framework to address pedestrian safety, accessibility, and infrastructure needs on Gibbons Drive while preserving mature Liquidambar trees wherever feasible, the exception would eliminate the need for repeated reviews by the Planning Board and City Council below that threshold. All other Tree Removal Policy requirements, including preservation evaluation, reporting, public notification, protest, or appeal rights.
Community Engagement
Since outreach on the Plan began in July 2025, staff have held six community meetings, online engagement opportunities, direct mail and email notifications, door-to-door outreach, and other opportunities for community members to provide input. On October 2, 2026, the City released the draft Gibbons Drive Sidewalks and Trees Plan for public review, with a comment period extending through October 23, 2026. Staff presented the draft plan to the Planning Board on October 12 and the Commission on Persons with Disabilities on October 14. In addition to that formal review process, some community members have requested, including a detailed proposal from Mark Minor, that the Gibbons trees be added to the list of protected trees subject to HAB review via the Certificate of Approval process. Mr. Minor’s proposal is attached as Exhibit 4.
Urban Forest Plan and an Updated Tree Preservation Ordinance
The City has also been developing an Urban Forest Plan to update and replace the 2010 Master Street Tree Plan. The draft Urban Forest Plan establishes a citywide framework for maintaining and expanding Alameda’s urban forest cover, with an emphasis on canopy preservation and expansion, species diversity and resiliency, equitable distribution of and investment in Alameda’s tree canopy, and effective long-term tree management. A proposed near-term action in the draft Urban Forest Plan is to develop an updated, expanded tree preservation ordinance that protects healthy mature trees and requires replacement or mitigation for tree removals.
DISCUSSION
Amending the List of Protected Trees in AMC 13-21.7
As this report demonstrates, the City has established multiple layers of protection for preserving healthy street trees. In addition to the protected tree designations established under Alameda Municipal Code Section 13-21.7, the City subsequently adopted its Tree Removal Policy, which provides additional safeguards governing tree removal decisions. Designating the Liquidambars on Gibbons as protected and subject to AMC 13-21.7 would require City Council to adopt an ordinance amending the AMC. On October 20, 2026, City Council approved a referral to bring an ordinance amending AMC 13-21.7 to include the Liquidambars on Gibbons Drive as protected as an alternative to staff’s recommendation to adopt the Plan.
Staff Work Plan, Capacity, and City Council Priorities
The City Council sets priorities for, and the City Manager manages the staff team’s work plan. Staff have limited capacity and must manage taxpayer funds responsibly and equitably. The City Council adopted the Strategic Plan in 2023 to guide staff’s work. Boards and commissions play a key role in representing community interests, advising staff and City Council, and implementing the City’s strategic priorities. This HAB workshop provides a valuable opportunity for the community and board to provide perspective on how the City identifies protected trees, specifically in the context of the proposed Gibbons Drive Sidewalks and Trees Plan.
The management of the City’s street trees is a uniquely complicated part of public infrastructure. The urban design and environmental value of street trees are a priority. However, decisions about tree management also need to take into consideration the requirements for safety and ADA path of travel for pedestrians, cyclists, and vehicles, as well as the function of underground and surface infrastructure, and the needs of adjacent private property. In addition, tree management decisions must also be made taking into consideration tree health and age, the mix of existing species nearby, soil conditions, and the impact of evolving climate conditions.
Conclusion and Next Steps
No healthy, mature Liquidambar trees on Gibbons Drive will be removed before the City Council has an opportunity to consider the extensive planning and community engagement process the Plan has had. Staff will consider public comments from this workshop, along with all other feedback received, and summarize the board’s input for City Council's consideration of the Plan.
ENVIRONMENTAL REVIEW
This item is for discussion purposes only, and no approval or action is being taken at this time, and it is therefore not a project for purposes of the California Environmental Quality Act (CEQA). If future action is taken on the matters discussed in this report, the respective decision-making body will make the appropriate considerations under CEQA.
RECOMMENDATION
Hold a study session to facilitate community and Historical Advisory Board discussion of the Liquidambar (sweetgums) street trees along Gibbons Drive in the context of the Protected Trees section of Alameda Municipal Code Section 13-21.7 - Interim Review, the process for amending the list of protected trees, and the proposed Gibbons Drive Sidewalks and Trees Plan.
Respectfully Submitted,
Brian McGuire, Acting Planning Services Manager
Exhibits:
1. AMC Section 13-21
2. Tree Removal Policy
3. Draft Gibbons Drive Sidewalks and Trees Plan
4. Minor Proposal