Eyes versus lungs
What is more important for a park - a nice scenery to please the eye or a better ecological effect to comfort the whole body?
Simple as the question looks, it has become the center of a hot debate between some local officials and scholars.
On one side are scientists who doubt the real effect of the many public parks constructed by the government lately.
"The large blocks of lawn, beautiful as they are, don't have much ecological effect," said Da Liangjun, an ecologist from East China Normal University.
Yet on the other hand, Guan Qunfei, an official with the Shanghai Landscape Committee Office, argued that the main function of the green spaces in urban areas was to beautify the city.
"Given the limited area downtown, it is almost impossible to achieve the ecological effect the scholars hope for," he said, admitting that the suggestions from the academic circle were good but not practical.
"If the whole city is compared to a human body, the green land in the city centre is like the eyes, and it is the forests in the suburbs that take on the role of the 'lungs'."
While according to ecologists, it would be better if the city could make full use of its limited area for parks and achieve as much environmental benefit as possible.
"The current situation is that the city has placed too much of its attention on mere appearance, neglecting the more important needs of the locals - a better ecological environment," Da said.
Take the Yanzhong Green Space for example. The area, which is located between bustling Huaihai Lu and Yan'an Lu, was landscaped three years ago after moving a lot of the former residents out at a cost of more than 100 million yuan (US$12 million) per hectare.
"Yet this so-called masterpiece of Shanghai is still not qualified as an ecological park as most of the species there have been artificially forced together," said Wang Rongxiang, another ecologist from Fudan University, interviewed by the Jiefang Daily.
Beautiful as they look, the artificial combination, instead of following the rules of nature, can affect the healthy growth of trees, and dilute their biological effect.
Research into the city's green space has found that there are altogether 142 types of trees there. However, only 11 of them are indigenous species, making up 7.8 per cent of the total. Add those which occur in neighbouring cities and the percentage goes up to 18.4 per cent.
"The large use of foreign species follows the current popular landscaping theory - pursuing a variety of species - but the landscape designers might not know that certain tropical trees like Washingtonian filiferra and butia capitata are not suitable for Shanghai," Da said.
"It is often the case that the city spends a lot of money importing them and maintaining them, while their help to the environment is very limited."
There is still another worry - can the city afford such large maintenance costs for its "artificial forests"?
Xia Xina, chief engineer with the Shanghai Afforestation Administrative and Directive Station, said the government's funds for greenery maintenance were very limited compared with the demand caused by the large scale forestation work of recent years. She and some other experts are now pleading to the government for additional funds to maintain the local parks.
"If the follow-up management can't keep up with the construction process, it could cause great waste and even become a major social problem," she said.
While in Da's eyes, many of these problems could be easily avoided if the government were able to reduce its interference into the choice of plants and pay more respect to nature.
After over 10 years' study in Japan, Da said he quite likes the green spaces in some parks there. They are not so delicate as the green spaces in China, but wild and overgrown with weeds. Yet every day they attract many birds and refresh the atmosphere.
Obeying the laws of nature is an approach that not only helps reduce maintenance costs (perhaps requiring no maintenance at all), it also ensures the most healthy growth of trees and thus achieves the biggest "biomass live-weight", Da said.
However, it seems that the government cannot set its heart at ease without doing something to the plants. Da cited an example of the so called "ecological forests" near the outer ring road. The large use of single type trees, neat as they look, is making the timber especially vulnerable to insect pests. This in turn means that the heavy use of chemicals not only requires large sums of money, but also results in more pollution.
Some experts suggest that local parks should be planted with more local or neighbouring species and the trees should be arranged according to the basic rules of the forest.
"Anyway, what we want is true nature instead of urbanized gardens," said Chen Xianshu, a local white-collar worker, whose opinion was said to be shared by many of her young colleagues.