From its sunny coastlines to its lush greenery, natives and travelers alike recognize California for its extraordinary landscapes. However, a recent study by a group of California scientists say one significant feature of the West Coast is on the decline: large forest trees.
Published in the journal Proceedings of the National Academy of Sciences, the study compared forest surveys from the 1920s and ’30s to recent U.S. Forest Service data. Revealed on Tuesday, what researchers found was discouraging: an astonishing 50% drop in big trees, like pines, since the 1930s.
The extent of the species’ disappearance suggests global warming and its effects is more than just a contributing factor, according to All Gov.
“Older, larger trees are declining because of disease, drought, logging and other factors, but what stands out is that this decline is statewide,” said study leader Patrick McIntyre, who manages biodiversity data for the Califonia Department of Fish and Wildlife. “Forests are becoming dominated by smaller, more densely packed trees, and oaks are becoming more dominant as pines decline.”
The study found that drought, changes in land use, and fire suppression efforts have caused the number of trees larger than two feet in diameter to decline by half in a 46,000 square mile area of the state’s forest they examined. The new, smaller trees don’t take in nearly as much carbon as the bigger trees, removing one of nature’s major shields against manmade onslaught.
“There’s no question that if you are losing large trees, you are losing the standing carbon in the forest. Loss of these big trees and the impact of drought stress become a big concern going forward in terms of its impact on the carbon cycle; they can turn a carbon sink into a source of carbon released to the atmosphere,” co-author and professor of integrative biology at UC Berkeley David Ackerly said, sounding a warning fleshed out with data in the study.
With California currently suffering a serious four-year drought – which the study did not factor in as the census was taken beforehand – the future does not look favorable. Climate models currently forecast that the state and much of the Southwest will continue to get warmer and drier in the future.
Dense forests packed with small trees also represent an increased fire hazard – a plight California already struggles with. But the compact shrubs now just make it easier for fire to travel and expand.
Princeton forest ecologist Willian Anderegg told National Geographic that the findings are another sign of the “shrubbification” of western forests in the US.
“The loss of these majestic largest trees is a pretty emotionally powerful thing to think about,” he said. “These are often the trees that have been around for thousands of years. It’s kind of a less magical future having lost those trees.”