Forty years ago this month then president Richard M. Nixon signed the Endangered Species Act, a vital piece of legislation that has been called one of the world's most effective environmental laws.

One recent beneficiary of the legislation is the Santa Cruz cypress. The California evergreen thrives after natural forest fires, which serve to open its cones and release its seeds. As humans have settled in the surrounding Santa Cruz Mountains and learned to bring fires under control, the tree has suffered. When the U.S. Fish and Wildlife Service added the cypress to the endangered list in 1987, its few remaining groves were imperiled by development.

Today those threats have mostly abated. Four of the five remaining Santa Cruz cypress habitats are now parklands or ecological reserves. The population comprises a healthy 33,000 trees or more, so the fws has proposed reclassifying the species as merely “threatened.”

Only a handful of protected species have ever rebounded enough to be delisted entirely, but like the cypress, most have stabilized and survived. “We view success as preventing a species from going extinct—to keep it from sliding further,” says Gary Frazer, assistant director for endangered species at the fws. “We've been very successful at that.

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