City planners in China are trying to take urban residents where they come from, to the forest.

Building an ecological city to make urban communities enjoy more green and healthy environments has become a fashion in many Chinese cities.

However, as more Chinese cities are queuing up to build "forest" cities, experts are ringing alarm bells.

The concept of the forest city was introduced to China in the 1990s, when Chinese citizens started to become concerned about their deteriorating living environment.

In fact, as early as in the 1960s, the concept of the "tree city" had already appeared in North America, which encouraged more tree plantings in cities.

It was acknowledged that trees and forests play significant roles in the urban environment and have many important meanings for urban residents, such as beauty, shade and shelter.

Citizens could purchase food labelled as healthy and green, transported from rural areas. But for clean and fresh air they breathe everyday they could only depend on their living environment.

"The tree city concept later evolved into today's forest city. Actually, it simply further developed the original green city model," said Wu Zemin, professor of College of Forestry and Gardens with Anhui Agricultural University, who had been keeping a close watch on city forest developments since 1989.

So far, more than 20 cities in China have put it at the top of their agendas to raise the forest coverage rate.

Green city in dispute

In recent years, to speed up forest city construction, some cities have even dug up big trees on mountains and replanted them in streets.

Such movements surely affect original balanced bio-systems and leave hidden dangers of erosion and sandstorm, according to Peng Zhenhua, chief scientist of the Chinese Academy of Forestry, who delivered a speech at a recent forest forum.

What the forest scientists criticized most was the construction of large-scale squares in cities.

According to Zhu Ning, professor of the forest department at Northeast Forestry University, many city squares are generally of an unreasonably huge size, as local governments believe they highlight achievements in urban construction.

However, there is usually no trace of trees on these squares, despite some rockeries and sculptures.

In summer, when people take a walk on the square, the scorching sun could even make them faint. Even at night, it still feels like being in an oven.

Large patches of neat lawn on the square were also frowned upon by forest experts, because their biological function does not reach one-tenth of that of trees.

What's more, alien species of lawn cultivated for the cold season drinks a much larger amount of water to sustain its growth and should be irrigated at least once in a day. Undoubtedly, these lawns have aggravated the water shortage problem in cities.

Especially in northern cities, dry and cold temperatures in winter are unfavourable, thus incurring a high maintenance cost.

"In the past, owing to an excessive worship of the western garden-building concept, when city planners make a choice between beautification effect and biological effect, they tend to take the former one," said Wu.

The garden design concept was even applied on streets. Nowadays, streets are much wider than before, but the greenbelt in the middle is commonly beautifully shaped with bare bush of little ecological value.

Suggestions for improvement

To establish an ideal ecological city forest system, professionals have put forward their suggestions.

At first, tree species should be diversified. The percentage of tall forest should be increased because it has richer ecological functions.

At present, ornamental trees or lawns are commonly imported species. They look pretty but are lacking in ecological effects.

Many cities introduced trees that bloom or grow colourful leaves. These species are not only low in survival rate, but also require a much higher maintenance cost.

"So we should give more priority to local plant species," said Wu.

Establishing an interdependent diversified native vegetation system, including high trees, bush and grass, would achieve the most favorable ecological environment, according to Wu.

If the forest is called the lung of the city, then the rivers and lakes should be its kidney.

Professor Peng Zhenhua advocated that establishing a sound water network close to the forest in the city would contribute to better ecological recycling.

The forest city is by no means feasible for all cities, especially for those situated in plains, which are traditionally surrounded by farmland, experts said.

"The urban forest itself is a complete ecological system, covering not only the urban areas, but also the suburbs," said Wu.

Large patches of forest in the suburbs are an essential prerequisite for developing a forest city.

Yet, the total amount of trees in the city proper is relatively small in cities built in plains and is also distributed unevenly, thus only playing a limited role in improving the biological environment there.

As the first city in China to construct a forest city, Changchun, capital of Northeast China's Jilin Province, boasts a glorious forest background. In its suburbs, there are distributed tens of thousands of acres of natural forest.

A newly rising star, Guiyang, capital of Southwest China's Guizhou Province, became the first city to be awarded the title of "national forest city" at the first city forest forum held last November.

Guiyang is a mountainous city and 34.8 percent of its administrative area is covered by forest.

Besides the completed forest belt around the city of 70 kilometres long covering an area of 9,066 hectares, Guiyang is now investing in building a second forest belt with a total length of 304 kilometres and a dimension of 21,333 hectares.

"Though it is hard for cities built in plains to build forest cities in the real sense, it is still necessary and also feasible for them to grow more trees in the urban areas. Anyhow, the ecological contribution of the greenery patches cannot be compared to that of trees," said Wu.

As the construction of city forest is ultimately serving the interests of citizens, providing them a calm and natural living environment, Wu suggested that city planners should "listen to the opinions of the public."

"Without their understanding and participation, a forest city would be meaningless," said Wu.

(China Daily February 26, 2005)