Street Tree Plan Updated to Address Fire Safety, Climate Concerns

The city is updating its Master Street Tree Plan to address fire safety, climate resilience, and biodiversity concerns that have emerged since the current plan was adopted in 1976.

The Department of Public Works will present an information-only update on the plan to the Municipal Services Committee on Tuesday, July 8, at City Hall.

The Master Street Tree Plan guides what tree species are planted throughout the city. But officials say the current plan has become overly prescriptive and lacks flexibility.

A preliminary report from the Public Works Department said the city’s approach has prioritized landscape uniformity, a common practice from the City Beautiful Movement. However, the amendment process is not keeping pace with changes in arboriculture.

The report showed the department is developing a policy framework that would make the plan more adaptive. The updated approach would give staff more discretion in tree selection.

The new framework follows the “Right Tree, Right Place” principle and includes specific toolkits for different scenarios. These include fire-resistant species, climate resilient options and biodiverse species.

The plan also incorporates the “10-20-30 Rule” for tree diversity. This rule states that no more than 30% of the urban forest should be from the same family, 20% from the same genus, and 10% from the same species.

The approach aims to prevent major canopy loss if disease or pests affect certain tree types.

The city has identified concerns about species appropriateness for location, biodiversity, climate resilience, fire risk and compatibility with eight updated Specific Plans.

Public Works earlier presented the conceptual update to the Urban Forest Advisory Committee in May and June. The committee received the proposal with general support.

The current Master Street Tree Plan evolved from a 1940 Street Tree List created by the Parks Department. The 1976 version incorporated the city’s growth and subdivision while maintaining consistent landscape design.

The plan was later incorporated into a GIS map and updated as needed. Species have been amended due to poor performance, including high mortality rates and maintenance concerns.

The report showed the updated plan will include four draft guiding principles covering public safety, climate resilience, biodiversity and placemaking considerations.

For areas within fire hazard zones, staff would use a fire-resilient species toolkit when the current plan designates fire-prone species.

The city plans to build toolkits using resources from UC Davis Climate Adapted Tree Species, Pasadena Audubon Species for Biodiversity and CalPoly SelecTree tool.

Next steps listed in the report include continuing development of guiding principles and presenting the draft to the Urban Forest Advisory Committee, Design Commission and City Council for final adoption.