Urban trees in Southern California are under increasing stress from extreme heat, long drought cycles, soil challenges, and new invasive pests. Research shows that hotter temperatures and shifting climate patterns will increase the risk of canopy loss in neighborhoods that already have limited shade. The Climate Ready Trees Study notes that rising temperatures, changing precipitation patterns, and increased salinity in reclaimed water will create significant challenges for many of the region’s traditional tree species (McPherson et al., 2016).

Neighborhoods like Canoga Park experience some of the highest surface temperatures in Los Angeles. Because of this, selecting trees that can tolerate future conditions is essential. The Climate Ready Trees Study explains that past tree selection focused too heavily on aesthetics, while future selection must be based on resilience and the internal traits that allow trees to withstand heat, drought, pests, and other 

stressors (McPherson et al., 2016).

The study emphasizes that many species commonly planted in urban areas today will not survive the environmental pressures expected over the next several decades. McPherson et al. (2016) explain that species must be able to handle increased heat, inconsistent rainfall, stronger storm events, and a growing number of pests that thrive in warmer climates. These findings help guide WRL as we consider species that offer long-term resilience for communities that are already vulnerable to extreme heat.

The Climate Ready Trees Study developed a scoring system to evaluate species based on drought tolerance, heat performance, pest resistance, soil and pH compatibility, canopy potential, and biological interactions. Trees were assessed across multiple Southern California climate zones, including the Southern California Coast region that covers the San Fernando Valley. This system helped identify species that show strong potential to survive and grow under future conditions (McPherson et al., 2016).

To create the final list, researchers combined expert recommendations with tree inventory data from several cities. They selected twelve promising species for each climate zone. These included Ghost Gum, Desert Museum Palo Verde, Netleaf Hackberry, Maverick Mesquite, Island Oak, Canby’s Oak, and Tecate Cypress. Each species demonstrated important traits such as drought resilience, heat tolerance, and pest resistance, which are critical for long-term success in hotter climates (McPherson et al., 2016).

The study explains that many urban species have not been tested under long-term climate stress. As climate conditions continue to change, both trees and residents in urban neighborhoods will face increasing risks. McPherson et al. (2016) highlight the urgency of creating climate-adapted species lists to protect public health, reduce heat impacts, and build a more resilient urban forest. This is especially important in disadvantaged communities where a lack of shade contributes to higher temperatures and increased vulnerability during extreme heat events.

Wildfire Resilient Landscapes is in the early stages of development and does not yet have formal partners or project sites. Even so, we are preparing our foundation by studying high-quality research that can guide future planning. The Climate Ready Trees Study helps us understand which species are best suited for hotter summers, longer drought periods, and the environmental challenges that shape Los Angeles.

We plan to use this information to guide our future planting strategies, species selection, soil preparation, and community education. Our goal is to ensure that any future WRL plantings are grounded in science and have the best possible chance of survival. As we grow, we will continue building a research-informed approach that supports urban resilience, healthier neighborhoods, and a stronger canopy for generations to come.

McPherson, G., van Doorn, N., Berry, A., Downer, J., Hartin, J., Haver, D., & Hodel, D. (2016). Selecting trees fit for the future (Study Plan No. UESD-16-002 EGM NvD). USDA Forest Service, Pacific Southwest Research Station, Urban Ecosystems and Social Dynamics Program.