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Sustainable Claremont’s Letter Regarding the City’s Tree Removal/ Mitigation Plan

By April 12, 2023May 12th, 2023No Comments

March 14, 2023

Dear Claremont City Council, Members of the Community and Human Services Commission, and City Staff:
We want to first express our gratitude to all of you for assessing our urban forest in the wake of last year’s windstorms and for proactively planning for possible tree hazard mitigation needs to ensure our community’s safety. Thank you also for your responsiveness to community concerns (by postponing the agenda item from the March 1st Community and Human Services Commission meeting) when it became clear that members of the community and close city partners like Sustainable Claremont had not been aware of these plans and deeply wish to be involved.

We are grateful for observant community members who fortunately happened to notice and then alert us to the proposed mitigation plan, without whom this mass tree removal decision may have gone completely under the radar. In the future, we would like to be included before mitigation plans like this are proposed to our City commissions and Council. And due to the significance and irreversible nature of their decisions, we would also like to see the City’s Tree Committee composed of at least one expert from a related field (ie. urban forestry, arboriculture, landscape architecture).

There is widespread agreement that our urban forest and the large trees remaining in our city are one of our community’s greatest assets. Large shade trees like our Coast Live Oaks, Sycamores, and, even Italian Stone Pines and Canary Island Pines are not just stately but also sequester enormous amounts of carbon, cool our businesses and homes, reduce the urban heat island effect, improve air quality, capture and slow rainwater, and support biodiversity while providing essential habitat for birds and other wildlife. They also increase our community’s economic vitality by attracting visitors and boosting property values. They even strengthen community mental health. Research has shown that many of these societal benefits are not fully realized until trees have grown to a mature size. Because of this, more careful consideration of the removal of individual mature trees is warranted.

Many trees are removed due to their negative impacts on urban infrastructure, such as those being proposed here, without a sufficiently thorough inspection of tree condition and risk of failure. Our response should be proactive to identify trees most at risk, not by species but by careful and detailed individual tree risk assessment. We believe that additional expert review/input should be undertaken including a third party Urban Forester with Municipal Specialist and Tree Risk Assessment certifications. This third party should undertake the following: at minimum, a level two risk (basic assessment) for all trees proposed for removal before approval; consultation with other cities (Pasadena, Santa Monica) working proactively to solve sidewalk issues without tree removal where possible; and landscape architecture/horticulture review by plant experts like Bob Perry (Architectural Commission) to ensure that replacement trees are appropriate for our changing climate and provide similar ecological and anthropogenic benefits to the trees removed.

While windstorms like we experienced last year are not common, these and other stressors are likely to become more frequent under climate change. But tree removal based only on species and a level one visual risk assessment is not a best or common practice and sets a bad precedent for the justification of future tree removals. A tree that is potentially high risk should not be removed before a more thorough risk assessment is completed.

We are wholeheartedly supportive of the need to assess and mitigate risks for the residents of Claremont, and these risks should be understood as potential hazards not only from trees but also to our trees. A healthy and very large urban forest is important for mitigating both air pollution and rising temperatures, and is especially important during dangerous heat waves. The greater Los Angeles area has seen average temperatures rise by 6°F in the last 50 years due to the loss of tree coverage and the increase of heat-absorbing roads and buildings. As temperatures continue to rise due to climate change, trees become an ever more important tool by cooling our cities by up to 10°F through the shade they provide and by releasing water vapor via transpiration. Any plan to remove trees should be part of a larger plan to grow the canopy and weigh the risks of individual trees with the benefit of a large urban forest here in Claremont. In other words, we are advocating for a more holistic risk analysis that keeps sight on the long-term benefits of trees.

In conversation with local arborists, we have learned that there are many tools in the toolbox outside of tree removal, which should be considered only as the last solution. For instance, there are solutions for fixing sidewalks without cutting roots. Rerouting the sidewalk around the trunk and root flare, shaving of the sidewalk, bridging the sidewalk over roots and using flexible paving materials are just a few of those options. We refer you to Bartlett Tree Experts document on removal alternatives as well Dr. Larry Costello and Dr. Katherine Jones’ Reducing Infrastructure Damage by Tree Roots: A Compendium of Strategies published by the International Society of Arboriculture.

While some tree removal may be warranted, mitigation for removed trees should also be adjusted to more closely equate to the assets and ecosystem services lost by their removal. Consider a commitment to mitigation of three to four street trees for every tree removed (or some appropriate number based on “DBH”–diameter at breast height). And finally, we must consider the importance of not removing trees between February and September due to the enormous, negative impact on our local bird populations.

In the future, the City of Trees and PhDs should do its best to call on some of its many area experts to ensure that trees are removed and are mitigated only when the risk is high and the hazard documented, which means undertaking a more rigorous approach and more detailed risk assessments. This will come at an expense but the benefits of saving even a few of our largest trees, would outweigh these costs. We welcome the opportunity to partner with you in these efforts.


The Board of Directors and Executive Director, Sustainable Claremont

Tree Policies and Guidelines Manual Update