Eighty-five percent of California schools considered in a recent study experienced tree canopy loss between 2018 and 2022.
Research published by a team from University of California (UC), Davis’s Department of Plant Sciences, which appeared in an article in the journal Urban Forestry and Urban Greening, showed a “mean net canopy change” of -1.8 percent during the period. Researchers used CALFIRE data on roughly 7,000 public urban schools to make this determination.
“The canopy decline was particularly acute in some districts, exceeding 25 percent,” according to the article. The “Central Valley emerged as the most dynamic region, exhibiting both pronounced losses and gains. These trends reflect the combined effects of redevelopment, environmental pressures, and uneven greening efforts. Overall, the decline in canopy cover is particularly troubling as climate change intensifies extreme heat and drought conditions.”
The most significant losses were identified in local educational agencies in Tulare, Fresno and San Bernardino counties. “Notably, these counties had relatively low canopy cover to begin with, making the observed losses even more concerning in terms of equity and climate resilience,” the article explains.
LEAs in Imperial, Kern and Stanislaus counties saw the most significant gains. “Additionally, we observed a clear cluster of positive canopy change rates across the Central Valley, including school districts in Madera and Santa Barbara counties,” the article states.
Two urgent needs emerged, according to UC Davis researchers, including “the expansion of canopy in low-shade, high-need schools, and the protection of existing tree cover in areas facing loss.”
Why canopy coverage is important
Most children spend the majority of their days on school campuses and schoolyards provide the only accessible outdoor green space some have.
“Schoolyards and their green spaces serve not only as educational and recreational spaces but also as key public infrastructure for addressing social and environmental inequities,” the article reads. “This is especially relevant in California, where schools often feature an open-air design and children might spend a significant amount of time outdoors. The quality of these environments has broad and systemic implications that could benefit approximately 12 percent of the U.S. student population who attend schools in California.”
Tree canopy is recognized as an effective strategy for improving outdoor thermal comfort, lessen exposure to extreme heat and ultraviolet radiation and support mental well-being and cognitive performance, according to research.
Schoolyards in the state have an average canopy cover of 6.4 percent, which is a concern as climate-related incidents become more common.
“Our findings underscore the urgency of targeted investments to protect California’s students and improve tree canopy in their school environments,” the article states.
Learn more in the article.
