More Heat, Fewer Giants

The future looks challenging for California’s big trees. By 2100, the state’s average temperature could rise by as much as 9°F compared to the late 20th century, raising the overall water stress for plants by 30 percent, said McIntyre.

Princeton forest ecologist William Anderegg, who was not involved in the new study, lamented what he called the likely “shrubbification” of western forests, as drier conditions encourage smaller, more tightly packed trees. "The loss of these majestic largest trees is a pretty emotionally powerful thing to think about,” said Anderegg. “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.”

Beyond their romantic grandeur, big trees play an outsized ecological role. They produce more seeds, resist wildfire damage, and store more carbon than their smaller brethren; rare animals such as spotted owls and flying squirrels live in their cavities.

The loss of such trees thus has important implications for the health of the Golden State’s forests, said University of Washington forest ecologist Jerry Franklin. “It’s not a happy prospect from the standpoint of a lot of different things,” he said.

Editor's Note: An earlier version of this story incorrectly identified the trees in the lead photo as Ponderosa pines. This is actually a collection of tall trees, including sequoias to sugar pines.

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Source: http://news.nationalgeographic.com/2015/07/world-population-expected-to-reach-9-7-billion-by-2050/