UC Santa Cruz Study Warns California Foundational Trees Face Habitat Loss of Up to 75 Percent by 2100

New UC Santa Cruz research warns that California's iconic trees could lose 75% of their habitat by 2100 due to climate risks missing from current global lists.

By: AXL Media

Published: Apr 25, 2026, 9:58 AM EDT

Source: Information for this report was sourced from EurekAlert!

A Stark Warning for California’s Botanical Identity

The geographic identity of California, defined by the silhouettes of Western Joshua trees and the fog drapes of the Redwood Coast, is facing an existential threat that exceeds current global conservation estimates. According to a study led by Blair McLaughlin at the University of California, Santa Cruz, the state’s endemic and near endemic trees are projected to lose between 50 and 75 percent of their climatically suitable habitat over the next century. Published in the journal Global Change Biology, the research indicates that traditional risk calculations fail to account for the accelerating pace of climate change, leaving foundational species far more exposed than previously realized.

Scientific Discrepancies in Global Conservation Rankings

A central finding of the research is the gap between the International Union for Conservation of Nature (IUCN) Red List and the actual risk posed by climate shift. The study demonstrates that even under conservative climate forecasts, most of the 27 foundational species analyzed qualify for higher threat levels than their current official statuses. While the Red List serves as an authoritative global reference for extinction risk, it lacks the regulatory power of federal laws, and the researchers argue that its current metrics do not yet reflect the imminent collapse of habitat suitability for species like the iconic blue oak.

Ecological Consequences of Blue Oak Woodland Loss

The blue oak, a tree found exclusively in California, serves as a vital component of the state’s inland rangelands and indigenous food systems. Senior author Erika Zavaleta and lead author Blair McLaughlin emphasize that these trees provide essential services, including carbon sequestration, soil stabilization, and nutrient cycling. If these old growth woodlands are lost, they are generally replaced by invasive grasslands, which lack the complex biodiversity and cultural significance of the original ecosystems. The study highlights that ranchers and wildlife alike depend on these trees for shade and habitat, making their potential disappearance an economic and environmental crisis.