Stone wall trees need better management

The hundreds of stone wall tress across Hong Kong enrich the urban ecology and breathe life into the city’s soul and character. Officials must ensure that these treasured assets do not become safety liabilities

PUBLISHED : Saturday, 05 May, 2018, 4:54am
UPDATED : Saturday, 05 May, 2018, 4:54am

Trees do not often make the news. But when they do, it is usually bad news, such as majestic heritage trees being cut down due to poor management or people being injured or killed by collapsed trunks. An exception was  a South China Morning Post report early this week.

After much delay, landscaping officials are finally exploring ways to better manage the hundreds of stone wall trees found in the city. 

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That it has taken so long for officials to recognise the need for a change is to be regretted. It has been three years since the Highways Department came under fire for hastily removing four century-old stone wall trees in the wake of a serious accident on Bonham Road. But if the studies being carried out by the government can offer better conservation, it is a still a positive step forward. After all, the typhoon season is coming. 

The challenges were mapped out by the government’s greening, landscape and tree management section – the tree office. Although these stone wall trees, usually banyans, have become part of our urban landscape for more than a century and did not seem to pose any major threat to people, the 2015 accident was a timely reminder that public safety cannot be taken for granted.

It is understood that 15 stone wall trees have been cut down over the past two years because of safety concerns, while at least five have failed on their own. 

The current guidelines have rightly accorded stone wall trees the status as natural and cultural assets that warrant special preservation. But the lack of scientific studies means their risks have yet to be fully appreciated.

These retaining walls were never designed to support tree growth. Even when they do not look dangerous under normal circumstances, strong wind and heavy rain add to the load and create the risks. To what extent the walls and the trees can safely coexist involves tree management and geoengineering expertise. 

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The stone wall trees have been honoured by some travel guides as an integral part of Hong Kong’s visual identity. They enrich the urban ecology and breathe life into the city’s soul and character. It is incumbent upon the tree office to ensure that our treasured assets do not become safety liabilities.