According to a new study from Humboldt State University, researchers were surprised to discover that the tallest tree in California's Muir Woods is only 777 years old—about half as old as they expected.

The tree-ring data marks the first time trees in the woods have been definitively dated. The 249-foot-tall redwood known as Tree 76 is likely one of the oldest based on its size. Its newly discovered youth indicates that the whole grove is probably much younger than its arborous neighbors to the north.

San Francisco's Save the Redwoods League is working with Humboldt State to document the age, size, health, and tree-ring history of the California old-growth redwood groves. In their long-term analysis, researchers hope to figure out how the behemoths are reacting to climate change.

Among their findings: the trees seem to be growing faster as they age, despite both environmental changes and recent dry years.

The oldest coastal redwood is about 2,520 years old.