Adaptation Strategies for a Resilient Urban Tree Canopy
By Emma Atkinson and Laia Menendez Diaz
Learning by Leading™ Urban Tree Stewardship interns (2020-2021)
As global climate changes from historical patterns, it is time to prepare for how these changes will affect our local landscapes.
The UC Davis Arboretum and Public Garden has partnered with Campus Planning to take leadership in developing the Living Landscape Adaptation Plan to conserve and adapt our diverse campus landscapes for future generations. This plan proposes three strategies to think about as we prepare for an uncertain future: resistance, resilience, and transition. These strategies share a common goal of ensuring the landscape continues to thrive in a changing climate by conserving what we can and adapting where we must.
Resistance
Resistance is an adaptation strategy that prioritizes the protection and conservation of at-risk, culturally important plant life.
Resistance focuses on the creation and maintenance of tree conservation areas and priorities, using tactics like rerouting trails or adapting irrigation to buffer against stressors. For example, our ancient heritage valley oaks (Quercus lobata) are highly valued culturally and ecologically, and our efforts will prioritize their continued success.
Resistance to oncoming threats can take considerable resources and thus requires a highly strategic approach. The Arboretum and Public Garden is a place where the community can come together to identify these priorities and work together to protect them so that our trees continue to shade generations to come.
Resilience
Resilience is an adaptation strategy that strives to strengthen tree populations through the attentive maintenance and adaptive care of our trees throughout their lifespan. One effect of extreme and changing weather, is an intensification of already abundant stressors on trees in urban environments. Preserving and protecting our current tree canopy must therefore reduce tree vulnerability to disturbance through risk management techniques.
Learning by Leading Urban Tree Stewardship interns are currently contributing to the resilience of our urban forest by developing a tool called the Oncoming Pests Project. This resource assesses potential invasive species and will help guide monitoring and treatment to prevent catastrophic losses. The Arboretum and Public Garden is dedicated to investing in the long-term stewardship necessary to keep our urban forest healthy.
Transition
Transition is a climate change adaptation strategy that converts a climate-threatened landscape into one more adapted to the future. This objective is accomplished by planting climate appropriate trees that will be less vulnerable to higher temperatures, less rainfall, and more frequent and extreme weather events. These actions are critical for the UC Davis campus, as only 30% of our canopy is anticipated to be well-adapted to the predicted climate of 2100 (LLAP Report).
As an active measure in transitioning the campus canopy, the Arboretum and Public Garden has developed the Texas Tree Trials, with funding support from the Saratoga Horticultural Research Endowment. Arboretum staff and students traveled to Texas to collect seeds of native trees that demonstrate potential in being better suited for the projected climate. The trees are currently being propagated and grown at the Arboretum nursery and field trials began in 2021 in the Arboretum.
Student leaders on the Urban Tree Stewardship Learning by Leading™ team have created a database to share research results, propagation and horticultural information about 46 trees with the potential to thrive in our future climate. This will be available to the public online. This research contributes to our larger purpose of serving as an example and resource in creating and maintaining a healthy and beautiful place where people and their environments thrive.