Questions have been raised about the effectiveness of the city's tree-risk assessment programme after a 29-year-old man was killed by a falling banyan in Tai Po yesterday.
It was the second fatality since the programme was put in place more than two years ago by then chief secretary Henry Tang Ying-yen, who was acting on recommendations after an investigation into the death of a teenager killed by a falling tree in Stanley in 2008.
The man, whom police have not yet named, was killed when the 100-year-old banyan fell on the truck in which he was travelling along a narrow road approaching Lam Kam Road, Tong Min Tsuen, Tai Po, at about 10.30am.
The 20-metre-tall, 10-tonne tree crushed the passenger side of the vehicle.
The 41-year-old driver escaped serious injuries and managed to climb out of the wreckage shouting for help, but his 29-year-old passenger - a delivery worker - was trapped inside. Firefighters took more than 1½ hours to free him and he was declared dead later in hospital.
In June 2010 a cyclist was killed when a diseased tree fell on him in Yuen Chau Kok, and a collapsing tree injured five people in Park Lane Shopper's Boulevard in Tsim Sha Tsui in July this year.
While the government is investigating the cause of the latest collapse, specialists at the site said the tree was sick and had been structurally imbalanced.
Sammy Au Wing-sum, president of the International Society of Arboriculture (Hong Kong), said the tree's branches had outgrown the trunk, increasing the risk of collapse.
The chief executive of the Conservancy Association, Ken So Kwok-yin, said the concrete road left little space for roots to grow and 80 per cent of the tree's trunk was rotten and believed to be infected with fungi and pests.
The government task force appointed after the 19-year-old girl was killed in Stanley in 2008 recommended trees on "unallocated sites" - which would include the one that fell in Tai Po yesterday - did not warrant a comprehensive assessment unless complaints were received.
"In view of the unique circumstances of departments concerned and resource constraints … the huge area in country parks and unallocated and unleased government land, which together constitute some 70 per cent of the total land area of Hong Kong, may not warrant a comprehensive exercise but would rather have to rely on identification of such trees through routine control and upon referrals and complaints," the report says.
Director of Lands Bernadette Linn Hon-ho conceded the tree, despite its location close to a highway and a village housing hundreds of people, was not checked by the department, which manages trees on unallocated sites. She said the department would assess trees more proactively in the future.
"I have already instructed colleagues to carry out an examination of the trees located in areas with high pedestrian and car flow, regardless of whether the department has received any complaints or not," she said.
So and Professor Jim Chi-yung, both of whom are members of the expert panel at the Tree Management Office under the Development Bureau, said the scope of assessment should be expanded to cover old trees on all government sites, wherever their locations. "Old trees are not necessarily risky. But they are weak without proper management, especially those in the New Territories," So said.
Jim proposed assessing trees taller than 15 metres. "Some unallocated sites are close to villages and busy roads," he said. "They should be a priority."