Satellite Data Reveals in Detail How California Loses Its Trees Due to Wildfires and Other Pressures

Using satellite data, researchers have quantified the loss of forest cover in California over the past 37 years. Their study showed how the trees in the state evolved from 1985 to 2021 as wildfire, logging, and drought severely damaged them and grasslands have taken over many parts where the trees were once abundant.

Study co-author Jonathan Wang explained that California had lost 6.7% of its forest tree cover in almost four decades, citing that most losses occurred due to the record-breaking mega-fires in 2010.

California Is Losing Its Wildflowers and Trees

In their study titled "Losses of Tree Cover in California Driven by Increasing Fire Disturbance and Climate Stress," published in the journal AGU Advances, researchers discussed the loss of California trees and wildflowers over 37 years despite the increased rainfall that reduced tree-cutting activities.

Study co-author James Randerson of the University of California-Irvine said that the forests are not keeping up with the large fires that resulted in big changes in less than four decades.

According to Newsweek, one of the most notable declines in the forest cover is in Southern California, where 14% of trees in local mountains vanished and may never come back. Wang said that this part of the state is considerably warmer and drier than the northern parts and the Sierra Nevada, which is why the tree population is already close to its limit.

Wang added that the rapidly increasing temperatures and prolonged droughts are preventing the recovery of forests from disturbances that prevent the seeds from germinating. At the same time, the coverage of shrubs and grasses is rising, which could foreshadow permanent ecosystem shifts.

The team thinks that the potential for "biome shift" may be replaced by grasslands in the future as forest cover dwindles. The next step for the team would be how it affects the Golden State's ability to sequester carbon and achieve a net-zero emission target.

Using Satellite Data to Describe California Tree Cover

The State of California is relying on its forests to help reduce the effects of global warming by storing carbon dioxide from the atmosphere. However, this natural climate change solution is in major jeopardy based on the satellite data researchers from the University of California used to conduct their study.

As wildfire, logging, and drought are killing the trees, fewer new ones are filling the void. According to NASA, the team used satellite data sourced from the US Geological Survey and the space agency's Landsat mission that was recorded between 1985 and 2021. Their paper is the first to quantify the decline of forest trees in California.

The American space agency said that researchers integrate remote sensing observation with the geographic information from the satellite data to create maps of the forest cover of California each year. Included in these maps are the trees, shrubs, and other types of plants that fire, logging, and drought severely affected.

The silver lining to their research is that the northern part has plenty of recovered trees from the fires that happened over the years. They believe this could be the result of higher average precipitation and the overall cooler temperatures in the region, despite the wildfires in 2018, 2020, and 2021 that burned a huge area and left a visible mark on tree populations.

Watch this news report from three years ago to see how the drought has affected trees in California:

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