The 70-foot-tall tree, hand-planted by Muir on his homestead 35 miles northeast of San Francisco -- which is now a national historic site -- is dying of an airborne fungus, the Los Angeles Times reported.
Horticulturist Kevin Park said he is working on saving the tree and may pursue creating a genetic replica, or cloning, the Muir tree.
Tree cloning is fairly common around Muir's homestead, but the task is usually performed on younger trees and is not successful on older ones, said William Libby, professor emeritus of genetics and forestry at the University of California Berkeley.
"We've cloned thousands of them in the 1- to 2-year-old class and never missed," said Libby, who is on the research committee of the Save the Redwoods League. "When you get to 6 [years old], you get some that don't work. By the time they're 20, most don't work. We've never [cloned] one beyond 80."
Park said he read this year the Archangel Ancient Tree Archive -- a non-profit based in Michigan -- has successfully cloned trees planted by George Washington at Mount Vernon.
Park has since sent the group healthy cuttings from Muir tree.
"John Muir himself had a hand in bringing it from the Sierra," Park said of the dying tree. "To me, it's a symbol of him and his love for the mountains, down here in the hot Alhambra Valley."