Embracing 242 trees over an area of 17ha, the forest surrounds Va Temple and has long been the relic's unique feature, said Phung Van Cuong, head of the relic management board.

Built between the 7th-8th century to worship Tan Vien God – who represents people's desire to conquer nature and overcome natural disasters – Va Temple and the surrounding forest has been recognised as a national cultural and historical relic since 1964.

Cuong, who is also deputy chairman of Trung Hung Ward where the relic is located, said dozens of trees had become rotten and died in the past few years, despite careful protection.

In addition, broken limbs had endangered tourists and local people.

Even though we have spread compost and nutrients and prohibited automobiles, the problem still remains, Cuong said, adding that saplings were also struggling.

While admitting their slowness to address the problem, he said local authorities were calling for outside help before it's too late.