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Rare Tree, Dependent on Fire, to Leave Endangered Species List

Natural forest fires were once an important part of the life cycle of the Santa Cruz cypress, a rare tree that today exists in just five mountainous groves in California.

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


Natural forest fires were once an important part of the life cycle of the Santa Cruz cypress, a rare tree that today exists in just five mountainous groves in California. Fires cleared out competing plants from around the trees and, crucially, the heat caused their cones to release their seeds—the main way the species reproduces.

Humans changed those fire cycles when they moved into the Santa Cruz Mountains. They built homes and businesses close to the groves, then added fire breaks to prevent natural fires from spreading. They also collected dead vegetation to stop fires from even starting. The cypress trees' life cycle quickly became threatened. When the U.S. Fish and Wildlife Service (FWS) the Santa Cruz cypress under the Endangered Species Act in 1987, the trees were reproducing at a very low rate and their few remaining groves were in danger of being cleared. A vineyard wanted to cut down half of one grove, and a residential developer wanted to completely remove another. Logging, oil and gas drilling, and the cultivation of related trees (which could hybridize with the Santa Cruz cypress) put the remaining groves at risk.

Today, after years of work, those threats have mostly been abated. Three of the tree's habitats are now protected as California state or county parks. Another has become an ecological reserve, and the fifth is owned by a private "conservation-oriented landowner," according to FWS. Newly enacted Santa Cruz County regulations have also limited development in the region. Although the species continues to be restricted to just 76 hectares of habitat, its population is relatively healthy, with at least 33,000 trees and possibly as many as 44,000. As a result of these successes, FWS now proposes (pdf) downlisting the species from its current "endangered" status to "threatened."


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The cypress is not completely recovered, though. Without regular fires, it may still need some human intervention to assist reproduction, which barely occurs in some of the groves. Researchers at FWS are now seeking scientific information on how proper management of the Santa Cruz cypress can help it continue to rebound. They also hope to receive comments on the proper taxonomy of the species, which was recently moved to a newly described genus, Hesperocyparis. Studies have also identified at least two separate varieties of the cypress that may require separate different management techniques. The public has 60 days to file any comments on these or other aspects of the downlisting proposal.

It only took the 26 years for the Santa Cruz cypress to recover—a rather remarkable achievement in the world of endangered species. This is definitely a success worth celebrating.

Photo: Kristina Barry, U.S. Fish and Wildlife Service

John R. Platt is the editor of The Revelator. An award-winning environmental journalist, his work has appeared in Scientific American, Audubon, Motherboard, and numerous other magazines and publications. His "Extinction Countdown" column has run continuously since 2004 and has covered news and science related to more than 1,000 endangered species. John lives on the outskirts of Portland, Ore., where he finds himself surrounded by animals and cartoonists.

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