A gardener in Beijing's Tiantan Park said sadly, "Many trees
that have stood for a thousand years are now dead." To cater for
the growing habits of grasses imported from Europe and America, the
park has had to introduce?sprinkler irrigation across large
areas of its gardens. But although this might be exactly what the
new grasses need, it has had an adverse effect on the native pines
that have watched silently over the park for so many years. They
can only thrive in dryer conditions and many have died. Now the
well intended innovations aimed at "greening" the park are being
questioned by experts and public alike.
Alien grasses: good greenery or bad
ecology?
In recent years, Tiantan Park, the Summer Palace, and Peking University's Yanyuan have
replaced indigenous species with grasses native to foreign coastal
areas. These new grasses need lots of water and this is something
that Beijing is short of. Spray irrigation has been brought in to
keep them healthy and green.
In fact, both citizens and experts have voiced their opposition
to the imported grasses. Ecologists have said, "The move is
wasteful in terms of both energy and money. It threatens our
ancient woodlands and the ecological balance."
Sprinkling irrigation once or twice a week in Tiantan Park has
resulted in too much moisture in the soil. Cui Haiting, a professor
with the Institute of Environmental Engineering at Peking
University found the herb
Rumex gmelini Turcz growing
among a group of pines. He said, "This herb belongs?to humid
areas, it should not be growing alongside the local pines."
Yang Zhenduo, former vice head at Tiantan Park, said that the
pines were exhibiting hydrotropism. What this means is that the
main locus of root growth tends to move towards moisture.
Previously in dry soil this had meant strong deep roots but as
moist soil is now concentrated near the surface, the pines are
becoming increasingly shallow rooted. There is a price to pay for
shallow roots in Beijing where strong winds blow in winter. Old
pines now no longer so well anchored in the soil, are being blown
over.
Environmental researchers have shown that these "cool-season"
grasses pose a further threat to ancient woodlands for they lead to
a less complex flora and a reduction in biodiversity.
"The pines in Tiantan Park and on Wanshou Hill in the Summer
Palace have several hundred years of history," said Professor Cui.
"The bushes and other plants that make up their undergrowth have
settled into an environmental equilibrium over hundreds of years
and are an integral and varied part of the pine and cypress
forests."
According to the experts, there are some 50 species of plants in
the pine and cypress forests of the Summer Palace and they have
counted 78 in Tiantan Park.
At first sight a forest of trees may appear to be a biologically
dull and uniform place but a good range of plants making up the
undergrowth can add variety and maintain a balanced and diversified
ecology. However the introduction of the "cool-season" foreign
grasses is turning the woodlands into genuinely monotonous
environments lacking even seasonal changes.
There have been knock on effects as new vegetation and soil
moisture content resulting from spray irrigation have impacted on
long-established animal habitats. Yang Zhenduo said, "Even
earthworms are seldom seen in the places where the 'cool-season'
grasses have been planted."
What's worse, the planting of "cool-season" grasses has actually
caused soil erosion. In the Summer Palace, grass planting on the
north slope of Wanshou Hill has been followed by the appearance of
bare areas crisscrossed by gullies.
Article 14 of the 1982 Florence Charter of the International
Council on Monuments and Sites (ICOMOS) states that:
"The historic garden must be preserved in appropriate
surroundings. Any alteration to the physical environment which will
endanger the ecological equilibrium must be prohibited. These
applications are applicable to all aspects of the infrastructure,
whether internal or external (drainage works, irrigation systems,
roads, car parks, fences, caretaking facilities, visitors'
amenities, etc.)."
Transplanting mature trees: a good move?
"The volume of greenery that can be provided by grassing is only
one seventh to one twentieth of the volume that trees can provide.
So transplanting trees into urban areas has become a quick cure for
'greening' the big cities," said Su Xuehen, a professor at the
Beijing Forestry University.
Trees are being moved from the courtyards of villages,
farmlands, mountain forests, and from "less important urban
sections" to "important urban sections". Officials from the Beijing
Garden Bureau said that there have been more and more "greening"
project like this in recent years. The trees have been making their
presence felt along the city's Airport Road, Fourth Ring Road,
Chang'an Avenue, and in local communities. Most of the trees
appearing there have been brought in from elsewhere.
"There's no stock of mature trees in the Beijing nurseries.
These new trees reaching up into the skies so quickly are bought in
from Shandong,
Henan,
Zhejiang
and Jiangsu
provinces," said Dong Xuexin, a businessman who helps the Beijing
Garden Bureau source large trees for transplanting. "And half the
trees are damaged in transit," he added.
Li Dihua, a botanist with the Institute of Environmental
Engineering at Peking University, confirmed what Dong had said.
"Trees that have lived for decades or perhaps even hundreds years
in the one spot have put down deep roots and spread out thick
foliage. They have developed a balanced relationship with the land
they live in. Transplanting comes as a trauma adversely affecting
their moisture content, roots and leaves, and being transported
just increases the damage," said Li.
Providing the urban market with its "overnight greenery" has
helped lots of people "grow rich overnight."
"A group of specialized traders has developed to service this
market," said Dong. "Some make a living exclusively by pursuing the
huge profits to be made in the purchase and resale of mature
trees."
"Transplanting mature trees has become popular in China's large
cities. One city government in a province in China's northwest has
even said it will invite 500,000 mature trees into its city within
the space of few months. Where will all the trees come from and how
many will be damaged in transit?" said Dong.
Beautifying the cities: harmony or
uniformity?
But is this beautifying of the cities, at the expense of disturbing
their ecological balance and depleting natural resources elsewhere,
really a success? Experts point out that real natural beauty is to
be found in harmony and balance rather than in clothing the
townscapes in a fresh evergreen uniform.
According to some experts, bringing in the "cool-season" grasses
has not only reduced diversity but has also damaged the overall
appearance of the landscape gardens.
Yang Zhenduo said that such species as Lagopsis supina,
Chinese violet (Viola philippica), and mother
chrysanthemum usually hold their leaves through to December in
Tiantan Park. Their natural shades of green and range of sweet
fragrances are always refreshing. But the green of the
"cool-season" grasses doesn't match the dark green, red, gray and
brown colors of the park. "It goes against artistic principles in
terms of both balance and coordination," said Yang.
And there are other aspects of the drive to beautify the cities
where the aesthetic perspectives are attracting criticism.
Prof. Su said that there is a current enthusiasm across the
country for creating scenes of distant lands. For example Beijing
has brought in tropical plants such as coconut palms, betel palms
and other palm trees to add a taste of the scenery of far off south
China to the northern capital. And for the sake of convenience,
man-made trees and flowers have been "planted" on some of Beijing's
squares and streets creating a sort of everlasting plastic
springtime.
What is even more difficult to understand is that artificial
plants are beginning to take root where the real ones are
found.
"Leaflet banyans (Ficus indica) are easy to grow in
south China. However, during the Kunming World Horticultural
Exposition in 1999, a large artificial leaflet banyan, was
'planted' in the exposition garden," said Su Xuehen. "It cost
several hundred thousand yuan and was made of polyvinyl chloride
which can burn easily giving off poisonous fumes."
Su said, "Misunderstanding of aesthetic considerations has led
to mistakes in the urban beautification drive. Deciduous woodlands
have been replaced by evergreen ones, native bushes by strange
flowers, and local grasses by alien ones. Moreover streets with
artificial landscapes and the century squares exposed to the sun
waste both energy and money."
Officials want to deliver quick results
"All officials hope to see achievements made during their term
of office," said Su. "However, tree planting is an undertaking best
viewed in the long-term and a desire for quick success can be
counter-productive."
Experts put the blame for the current popularity of tree
transplanting on a desire on the part of the officials to achieve
quick results and instant improvements.
There is an old Chinese saying, "while earlier generations plant
trees, posterity will enjoy their shade."
"Nowadays people are too impatient to wait for the shade. They
want to plant trees today and enjoy the shade today," said Su.
"Most horticultural managers are experts in gardening and fully
understand the great harm that large scale transplanting is doing
to nature. But they will choose to disregard what the experts are
saying and carry out the work due to a strong sense of duty to
their employers and out of loyalty to their superiors."
"Three groups of ginkgo trees are being planted in the current
Beijing south city planning project," said Yang Zhenduo. "The trees
will be 20 cm in diameter and they are to be planted only five
meters apart. This will look really good at the time of planting.
But at this spacing their branches will grow together in just a few
years. Logically they should be put in eight to ten meters
apart."
Yang speculates that the trees might be moving closer and closer
together because design and construction fees are related to cost
and increased costs mean higher fees.
Experts think that in the rapid process of urbanization, the
policy makers must take a broader view and local interests should
be subordinated to the general good. Only in this way can China's
growing number of urban citizens be provided with a sustainable and
healthy living environment.
(China.org.cn by Li Jingrong, July 14, 2004)
