A lone pine tree that stood as a symbol of hope in Japan, after surviving the huge tsunami that swept away a forest of 70,000, was being cut down Wednesday in a bid to preserve it.

The tree, which came to be known as the "miracle pine", will be sliced into pieces and treated before being put back together, in a process expected to cost about 150 million yen ($1.9 million).

A ritual reflecting the beliefs of Shintoism, Japan's animistic native religion, was carried out on the pine before the delicate process began on the shore at Rikuzentakata, a city badly hit by the March 2011 disaster.

"The process of cutting down could take two days or more, as we need to start cutting branches that can eventually be put back on the trunk," city official Shinya Kitajima told AFP.

He said the trunk of the 27-metre (89-foot) tree will be divided into nine sections, which will be hollowed out and given anti-decay treatment before being reassembled using a carbon spine.

The whole preservation process will finish in February, the official said, and the tree will be put back where it was, on a spot that was previously a thick shoreline forest.

A Facebook page launched earlier this year soliciting donations towards the cost of preserving the pine had raised nearly 27 million yen by Monday, a city official said.

Around 19,000 people died when the huge waves of 18 months ago swept ashore, crushing whole communities on Japan's northeast coast.

Hundreds of thousands of people remain displaced, either because their homes were destroyed or because they had to evacuate the area around the stricken Fukushima nuclear plant when it began leaking radiation.