Tree unit failing to spot the sick and dangerous, researchers say

Researchers want the government to look after trees better after finding more than half of 51 they examined were sick.

Underscoring the problems of trees in the urban area, Lam Tak-Chak, a committee member of the Institute of Horticulture Science of Hong Kong, said an autumn maple nearly 200 years old was dying.

The researchers, from the institute and Chinese University, examined 23 camphor trees and 28 Norfolk Island pines. They found 27 of the trees were unhealthy due to poor management. More than one in 10 were at risk of collapse, which could cause danger to pedestrians, the survey showed.

The government set up an office this year to co-ordinate the tree management work of various departments - fulfilling one of the recommendations of a review after a diseased tree fell down in Stanley two years ago, crushing a teenaged student to death. But the survey team said tree management was still unsatisfactory and a sustainable tree strategy was needed.

Professor Chiu Siu-wai, associate professor of life sciences, said: 'Eighteen of the camphor trees fell ill because they were badly taken care of. There are either holes or black spots on the leaves because they are infected by fungi or moulds.

'Some trees are grown in pots that are too small for them so they can't absorb sufficient nutrients. As a result, they are not leafy enough or the leaves are yellow or too small,' he said.

The study found the roots of some Norfolk Island pines had been severed during construction work.