Giant Sequoias Under Pressure from Climate Change

Giant sequoias, some of the world's oldest and tallest trees, are under pressure from drought, wildfires and climate change, according to scientists with the US Geological Survey.

Although sequoias aren't yet in trouble - even with the ongoing drought in California - scientists worry that them and trees alike, such as ancient redwoods and bristlecone pines, will soon be feeling the heat.

These types of trees aren't built to withstand decades of dry and warming weather. Their seedlings and saplings are vulnerable to forest fires, which are increasing, and constant drought will prevent the seedlings from developing a strong root system due to the lack of melting snow.

"If there's long-term drought, within 25 years, we could see seedlings in trouble," Nathan Stephenson, an ecologist with the US Geological Survey, told The New York Times. "In 50 years, the whole population could be in trouble," he continued, and within a century "most of the big trees could be gone."

Giant sequoias (Sequoiadendron giganteum), some of which are 2,000 to 3,000 years old, live only in 60-mile band of the Sierra Nevada Mountains in California, according to the US Department of Agriculture Forest Service. There are 33 groves with trees reaching towering heights of more than 300 feet.

But conservation efforts to protect sequoias from a seemingly dim future, according to The Times, is difficult given so little is known about them - from their root system to how they die.

As the climate changes, so do the conditions in which these trees grow.

"We might start irrigating the sequoias," Stephenson told The Times, "or we might build a giant fuel break around the giant sequoias, so if a fire came toward the grove, we could defend it. These things are getting hard discussion."

Wildfires brought in by drought and warming temperatures aren't the only factors posing risks to these big trees. Habitat fragmentation, air pollution and selective breeding for timber have already weakened many forests. Warmer temperatures can also usher in disease and insects, along with fire.

Although giant sequoias are resilient trees - they have eight-inch-thick bark and can recover from a fire even with 95 percent of its bark scorched - scientists still worry for their future well-being and believe everything should be done to protect them.

"We are talking about the loss of the biggest living organisms on the planet, of organisms that play a key role in regulating and enriching our world," Bill Laurance, an environmental scientist at James Cook University in Australia, stressed to The Times.