Tree experts on Tuesday blamed an inefficient system of tree planting, for the destruction of some 4,700 trees, during typhoon Vicente. The count of fallen trees continued to rise on Wednesday, one day after the typhoon signal was cancelled. Another more than 700 reports of fallen trees reports were received that day.

Chair professor at the Department of Geography at the University of Hong Kong, Jim Chi-yung, said the high number of fallen trees was "disappointing and should not have happened".

Jim said the typhoon shouldn't have brought down so many trees, especially small trees, which are quite resistant to strong winds. Jim attributed the large number of fallen trees to a mismatch among species of trees and insufficient underground space for roots to take hold. "The government planted trees, such as banyan, delonix regia, next to streets in constrained space. That prevents the roots from stretching out in a natural way. Those are the types of trees that need a lot of space underground to develop roots," said Jim.

Jim also was critical of the quality of saplings introduced into the city. "Most of the trees in Hong Kong are bought from the Pearl River Delta. However, the quality of those saplings does not meet with the standards adopted by developed countries. Thus, it has imported misfortune from the source," said Jim.

Jim suggested that the government should enrich the variety of trees in the city to add to the diversity. In addition, he suggested the government pay more attention to nurturing local tree species instead of buying the sub-standard saplings from outside.

Days before the typhoon struck on Monday, an over 70-year-old banyan along Nathan Road collapsed. Five passers-by were injured. The weather at that time was good. Subsequently, the Development Bureau carried out an inspection of the banyan and found the tree was consumed by fungal growth and was almost hollow inside. The expert panel of the Tree Management Office under the bureau will meet up on Thursday to discuss the follow up arrangements for two adjacent banyans, which shared the same earthen bed with the fallen tree.

Jim said trees collapsed even on normal days, without a typhoon, proving that the planting methodology in the city has problems.

Echoing Jim, the green group Conservancy Association's Chief Executive Ken So Kwok-yin said though Vicente had the capability to blow down healthy trees, half of the fallen trees toppled because of insufficient living space underground. So said, if the underground space is too small for the roots to grow and there is not enough earth to hold on to, the trees will fall easily.

According to the Leisure and Cultural Services Department, which manages about 400,000 trees, around 4,700 fell after the typhoon.

A Development Bureau spokeswoman said different types of saplings are bought by different departments and bureaus according to the planting environment and space. She also said the government has the direction which stipulated that enough space should be given to individual trees.

stushadow@chinadailyhk.com

(HK Edition 07/26/2012 page1)