California’s 39 million people don’t have enough shade, something Cal Poly and Cal Fire are partnering to combat. Together, they want to help boost the state’s tree canopy by 10 percent by 2035.
“The idea behind it is that we have hotter and hotter days in California, and we don’t have enough shade, so we call this the heat island effect,” Cal Poly biology sciences professor Jenn Yost said. “It’s where some of the poorest and most disadvantaged communities in California are experiencing the largest burden of climate change and heat-related problems.”
Project plans began after Assembly Bill 2251 passed in June 2022, which aims to promote policies and incentives that advance improved maintenance of urban forest canopy.
Leading the project with fellow Cal Poly biological sciences professor Matt Ritter, Yost said the collaboration between the university and Cal Fire is called the California Strategic Plan for Urban Forestry (CASP) and will focus on addressing issues of climate change, extreme weather, pollution, and drought in disadvantaged communities.
CASP will use data to measure canopy coverage statewide and identify areas that need improvement, prioritize biodiversity to ensure resilience against disease and environmental stressors, equip cities with goals and actionable strategies to expand the canopy in disadvantaged areas, and engage stakeholders to ensure effective implementation and community impact.
“Trees provide people with all kinds of epic ecosystem services. They provide shade—so the temperature can be 10 degrees cooler if you’re in the shade of a tree versus not,” Yost said. “They do stormwater mitigation, they protect cities from flooding and massive events like that, they provide clean air, they provide habitats for animals.”
Yost said that shady, green, and lush areas are present in wealthier communities, and this project hopes to expand those much-needed environments to disadvantaged neighborhoods.
“Trees are not just for the rich,” she said. “Some of these areas are concrete jungles, and they are incredibly hot, and those are communities where people walk and use public transportation, and they don’t have any shade on their sidewalks.”
CASP will receive help from Cal Poly’s Urban Forest Ecosystems Institute (UFEI), which has curated tools for the past 20 years to help work with trees.
UFEI is using AI remote sensing to pinpoint every tree in every California city to help locate areas that need more tree canopy.
“We also have tools that can tell you all the trees that are school friendly, and we can coordinate the California Big Tree registry tools that tells you every public tree that’s been inventoried in California,” Yost said.
Cal Poly economics, computer science, geography, biology, environmental management, and forestry students will help to tackle small components of CASP, Yost said.
While the outline of CASP’s plan was originally due to state Legislature by June 2025, Yost said the process has taken longer than expected, and the group is now working on a June 2026 deadline.
In the meantime, Yost said they’re working with the city of SLO on a tree campaign to help encourage a goal of planting 10,000 new trees.
“At Cal Poly, we track all those newly planted trees and count them,” she said. “If somebody plants a tree in their backyard, it counts toward that goal.”
To learn more about California’s trees, visit ufei.calpoly.edu. Δ
This article appears in Dec 5-15, 2024.