New Delhi, April 4 -- Many of Tokyo's popular and iconic Somei Yoshino cherry blossom trees were planted during Japan's postwar advancement in the 1960s, and are now getting old and frail.

Some have fallen and many others require support, triggering safety concern as the Japanese celebrate the season of their favorite flower.

Two cherry blossom trees collapsed on Thursday, one at Kinuta Park in downtown Tokyo and the other at the Chidorigafuchi greenway. The one in Kinuta Park damaged a fence while the other tree almost fell into the Imperial Palace moat, though nobody was injured.

The tree in Kinuta Park was 18 meters (59 feet) tall and 2.5 meters (8.2 feet) in diameter. It was among the oldest, believed to be more than 60 years old, ...