A massive ancient oak tree linked to the legend of Robin Hood may have been loved to death.

The 1,200-year-old Major Oak in Sherwood Forest is believed to have died after it didn't sprout leaves this spring, the Royal Society for the Protection of Birds said Thursday.

Visitors over the past two centuries who viewed the tree's gnarled limbs and sprawling canopy in Nottingham compressed the soil, making it difficult for rain to reach its roots, the conservation group said, despite the immediate area around the massive oak being fenced off.

The forest has been under threat for years and the tree had been rumored to have died in the past — only to have the group confirm it was still alive.

That is no longer the case.

"The tree's failure to produce leaves this year is heartbreaking for everyone," Hollie Drake of the Royal Society for the Protection of Birds said in a statement announcing the death.

The tree is said to have sheltered Robin Hood, the legendary 13th-century bandit who stole from the rich and gave to the poor and took refuge in the forest when being pursued by the sheriff of Nottingham.

It got its name after being mentioned in a book on oak trees by Major Hayman Rooke in 1790 that led to the first wave of fans who flocked to the forest.

It's impossible to say what killed the tree, but the footprints of millions contributed to its downfall, along with intervention to shore up its massive limbs using cables and poles. Climate change that has brought heat waves and drought was also blamed.

Tree experts found the root system strangled and starved.

"Ancient trees like the Major Oak are the 'conservation white rhinos of the U.K.' but their decline is far less visible," said Ed Pyne, of the Woodland Trust. "Saving them is vital to the health of the world we live in and yet most disappear quietly, without the recognition or care given to the Major Oak."

In addition to its place in folklore, the forest is known for Sherwood oaks that floated the ships of Vice Admiral Horatio Nelson's Royal Navy in the late 18th and early 19th centuries, and as timbers in the roof of St. Paul's Cathedral in London.

The Major Oak was spared from the saw and had been protected by a fence since the 1970s.

"Although this marks the end of the Major Oak as a living tree, it does not mark the end of its story," the Royal Society for the Protection of Birds said.

"The tree and soil beneath it will continue to be a vital refuge for wildlife and the knowledge we have gained by looking after the Major Oak will help preserve other ancient oaks across the country," the group said. "Its legacy will live on through its saplings and the legends associated with it, with plans being drawn up with our partners, and the tree will continue to be a vital refuge for wildlife."

Drake said the tree will be a monument that people can visit, "living on in the legend of Robin Hood and continuing to provide as much support to the forest's ecosystem in death as in life."