Robert Van Pelt
The Del Norte Titan coast redwood, at 307 feet one of the world's tallest trees, dwarfs two visitors in California's Jedediah Smith Redwoods State Park.
Researchers have put a theoretical height limit on the world's tallest trees. According to an article in the science journal Nature, it's difficult for California redwoods to drag water up much higher than 426 feet. The world's tallest known tree is pegged at about 370 feet. NPR's Ketzel Levine reports.