AMSTERDAM, Aug 23 (Reuters) - A giant chestnut tree that comforted Dutch diarist Anne Frank as she hid from the Nazis in an Amsterdam attic during World War Two collapsed in heavy wind and rain on Monday.

No one was hurt and the 150-year old tree fell across a fence, missing the Anne Frank House, which has been turned into a museum and was full of tourists.

"It broke off like a match. It broke off completely about one metre off the ground," a spokesman for the house said.

The tree was one of the few signs of nature visible to the Jewish teenager from the concealed attic she hid in for over two years during World War Two and it is mentioned in the diary which became a worldwide best-seller after her death in a concentration camp in 1945.

"Our chestnut tree is in full blossom. It is covered with leaves and is even more beautiful than last year," she wrote in May 1944, not long before she was betrayed to the Nazis.

The tree had developed fungus and was set to be felled in 2007 due to concerns for the safety of the 1 million people who visit Anne Frank's house each year.

But officials and conservationists later agreed to secure it with a steel frame to prolong its life and saplings from the tree were planted last year in an Amsterdam park and other cities around the world.

A Dutch tree foundation, which fought to keep the tree alive with another support group, said horticulturalists had estimated the tree could still have lived for dozens of years.

Arnold Heertje, a member of the Support Anne Frank Tree group said there were no plans to plant a sapling on the site or preserve the tree's remains.

"You have to bow your head to the facts. The tree has fallen and will be cut into pieces and disappear. The intention was not to keep this tree alive forever. It has lived for 150 years and now it's over and we're not going to extend it," he said.

Parts of the tree, located on a residential property adjacent to the Anne Frank House, were later being offered for sale on Dutch auction website marktplaats.nl. The highest offer was 10 million euros ($12.72 million). (Additional reporting by Ben Berkowitz; editing by Noah Barkin and Nina Chestney)