India, June 19 -- "Here stood a great oak tree with branches spreading broadly around, beneath which was a seat of green moss where Robin Hood was wont to sit at feast and at merrymaking with his stout men about him," wrote Robin Hood author Howard Pyle in his 1883 book.

More than a century later, that image continues to shape how millions view the Major Oak, an ancient tree in UK's Sherwood Forest whose fame owes as much to literature and legend as to its remarkable age.

The tree, between 1,000 and 1,200 years old, is believed to have died after failing to produce leaves this spring. But long before conservationists fenced it off and tourists travelled to see it, Major Oak had already secured a place in folklore, literature and popular...