Muir Woods: California's Tallest Tree Younger Than Previously Thought

Muir Woods is known for having some of the oldest, tallest trees on Earth, but a new analysis shows that California's tallest tree is actually younger than previously thought.

The 249-foot-tall coast redwood named Tree 76 is not 1,500 years old as scientists once assumed, but rather a more green 777 years old. That means this giant was born seven centuries later than originally believed, at the start of the Medieval Inquisition in the early 13^th century.

It also means the oldest and biggest tree found in Muir Woods, north of San Francisco, is just a baby compared to the huge trees located farther north.

"It's one of the largest redwoods in Muir Woods, so it probably represents one of the oldest," Emily Burns, science director for San Francisco's Save the Redwoods League, told the San Francisco Chronicle.

The new birth date was determined after tree-ring specialist Allyson Carroll, from Humboldt State University, compared the tree rings from Tree 76 to a database of core samples taken from redwoods across California. Based on the size and thickness of the tree rings, which are larger during wet years and smaller during dry years, scientists can relatively easily date trees back to a specific time.

But turning back the clock on Tree 76 is not all this new tree-ring analysis is good for. Scientists plan to use this data to also determine how these famous redwoods react to climate change. Currently, the collective redwood tree-ring record in California can reliably be traced back to the year 328, revealing drought years and other major weather events, Carroll said.

It turns out that the trees are growing faster as they grow older, despite climate change and the worst California drought in a millennium. The redwood forests all saw stunted growth around the year 1580, but in the last few decades tree growth has accelerated.

Redwoods "tend to grow in some of the wettest places in California," Burns told the Los Angeles Times. Although the state as a whole has seen little rain, especially during these last four years, redwood forests are in areas blanketed in fog, rooted in wet soil or at the foot of snow runoffs.

Until now, no one had ever definitively calculated the age of the trees in Muir Woods, but scientists have suggested that the tallest trees were probably 1,200 to 1,500 years old.

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