ISA HK/China --- Introduction to Urban Forestry

Dear Station Members,

At the Sep 06 CA Training by Arbor Global in Fung Kai School, the Station Manager was requested by two Station Members to write on two separate topics: Termites & Urban Forestry. Since Termites were then a more pressing topic, the 'Termite Talk' was quickly released in Station Mail in Oct 06. The Station Manager has not forgotten his pledge to write on Urban Forestry though. Now this is how an introduction of this immense topic is to be presented ....

The term of Urban Forestry seems to contradict itself. How can we call it a forest if it is situated in an urban area? Our normal understanding of Forestry would be those up in the hills with eco-system intertwined. The commercial interest of Forestry studies also seems to lie upon the economic value of wood for products. However, when we come to think of the trees in our parks, housing estates, roadside, community centres, institutes & other public places inhabited by population, it is not difficult to imagine that we do have a form of eco-system in our urban areas. Urban Forestry mainly intermingles with human activities, our city life.

Trees in our urban forest usually do not have the luxury of an ideal growing condition of the natural environment, but rather have to struggle for survival in an environment designed for human needs. For example, urban soil is usually depleted of organic matters & lacks microbial activities. Even if by adding in form of compost, once used up within a few months in our subtropical climate, topping up by natural process will be unlikely. Then there is the heat island effect, lack of growing space, drainage problem, wind gusts created by building structures & traffic, contamination by pollutants, human vandalism, incorrect planting practices & a whole range of other abuses to sustain. It is a miracle that our trees can survive in such hostile conditions at all ! Aren't trees forgiving??

Statistics in western countries showed that Street Trees usually have a Functional Life Span of only a few years. In 2004 in Los Angeles, some survey gave a result of only 7 years. Most of the roadside trees in HK would be regarded as an object for removal in terms of structure & health by international standards, & yet their retention seems to be a compromise between conservation & politics really. If our attitude towards trees comes any closer to that of the western countries, maybe at least half of our roadside trees will be a target of removal soon enough.

In countries practicing Urban Forestry, Urban Foresters will usually begin involvement at the planning stage of any development like providing Tree Survey, Arboricultural Assessment & Selection of Tree Species . Urban Foresters would generally report directly to the City Council & would be the second person on site after the Land Surveyor. They will decide upon which trees to retain, remove or transplant with their professional knowledge in accordance with the local laws. They are likely to advise on tree protection in construction sites & supervise the planting stages of nursery stocks selection, installation & subsequent maintenance. They would usually work alongside with other landscape professionals like the landscape architects, nurserymen, contractors & especially environmentalists. Urban Foresters would help the City Council to draft up laws & regulations in protecting trees in the urban setting.

Management of the urban forest is a subject of its own in a lot of western countries. In the regular maintenance sector, Urban Foresters would be involved in producing Tree Inventory, & carry out regular Tree Inspection to categorize trees for further treatment. For newly planted Young Trees in landscape, regular Structural Pruning will be a necessity to develop good health & structure. Landscaping trees with good health & structure will be much less prone to wind failure & pest attack. While in Singapore, the Station Manager has learned that the National Parks Board (Nparks) of the Singapore Govt carries out regular Tree Inventory, Tree Inspection & Structural Pruning in their Greenery program. Next time when you are here, admire their trees & think of the work they have input into their trees. Good trees in urban setting just do not come naturally.

In western countries, Urban Forestry is usually administered by qualified arborists in their City Forestry Dept. The GIS system is a popular method to carry out Tree Inventory. Regular Tree Inspection & Structural Pruning are usually executed by Certified Arborists & Certified Tree Workers, & rarely by common gardeners who have not been trained in the subject. Trees are a specialist topic & have to be handled by tree specialists, or we may be getting something else rather than a tree at the end. If this is not convincing, look at Leung King Estate in Tuen Mun that the Station Manager is involved at present... Look at how trees were mutilated there, in the name of 'Pruning'.

It will be inappropriate for this Station to compare the image of Urban Forestry in HK with that of advanced western countries. The Station Manager has learned that our Govt Depts are actually working hard on improving our tree scenery but have considerations on priorities & resources. After all, Singapore has taken decades to come to their excellent state of tree affairs of today, & we do not even have a City Forestry Dept in HK. May we hope in the near future that our loving city of HK can also produce well grown trees as compared to Singapore & may Urban Forestry sometime take its position in our world class city of HK some day.

best regards,

Sammy Au
Station Manager