Towards a Sustainable Housing Environment: Ecological Landscape Principles and Practices in Large Housing Estates of Guangzhou, China

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Towards a sustainable housing environment: Ecological landscape principles and practices in large housing estates of Guangzhou, China

Junyan He, Beisi Jia Department of Architecture, The University of Hong Kong [email protected]

Abstract Sustainable development of housing environment is of growing concern in China’s urban development. As the capital of Guangdong Province as well as the largest city in south China, Guangzhou is now experiencing a large-scale housing development. Residential landscape is considered as the main means of creating a comfortable housing environment. Large amounts of money have been invested in residential landscape construction. This paper aims at inves- tigating the ecological landscape principles for large housing estates in Guangzhou, China in order to lead toward a more sustainable housing environment. The study is divided into two parts. The first part builds up the principle framework based on related literature review on ecology and landscape, and puts forward ecological landscape as the form that can not only minimize environmentally destructive impacts but also cultivate a harmonious people-plants relationship. The second part of this paper evaluates the validity of the claim of ‘ecological estates’ and ‘garden estates’ in the housing market. The above five principles will then be used as parameters for case evaluation and comparison. The research findings suggest that towards a sustainable housing environment, what seems to be essential to an ecological residential landscape is neither the amount of finical resources that has been put into the landscape construction, nor the green-coverage-rate of the overall housing estate; but rather the abidance with the five ecological landscape principles.

Keywords Sustainability, housing environment, ecological residential landscape

1. Introduction: ecological landscape principles in housing development In 1992, the United Nations Conference on Environment and Development (UNCED) put forward the concept of sustainability, which is defined as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Some years later, sustainable housing development has become a growing concern in China (Liu et al., 2001; Zhang, 1998; Ren, 2000; Jia, 1999).

Landscape has a very close relationship with housing and buildings. Urban green areas, both public open spaces like parks and private planted areas around buildings, can have a marked effect on many aspects of the quality of the urban environment and the richness of life in a

city (Givoni, 1998). In the residential community, landscape can affect the housing in the surroundings. Different kinds of internal courtyards and attached enclosed open spaces may affect the housing climatic characteristics. It shows that landscapes have a very close relationship with housing environment.

Ecological planning and design seek to make nature visible and to develop ecological characteristics in landscaping (Van der Ryn & Cowan, 1996). Many studies criticize the human-centered tendency in landscaping where intensive human recreation and leisure activities may damage ecological processes, ecological integrity and system productivity. To move towards sustainable development, it is suggested that indigenous landscape patterns should be conserved, cultivated and revitalized (Platt et. al., [ed], 1994). In residential communities, ecological landscape addresses not only environmental protection but also the interrelationship between people and nature. Landscape planning and design principles should promote ecological integrity while forming a balanced social and physical environment. Landscaping should help to form sustainable communities that offer opportunities for participation that encourage new modes of interaction among residents. Human beings are living social groups and active participation by the residents can help to achieve sustainability (Grant et al. 1996). Planners cannot create sustainable communities without having the commitment from residents to modify or adapt their behavior or attitudes towards caring for the landscape around them. Residents may take part in the design process to express themselves in the surrounding environment; work together to take care of the landscape; or obtain knowledge about planting and ecology.

The formulated five principles are: 1.1 Applying indigenous plants The maximizing use of the indigenous plants is a very important idea in ecological landscape. A sustainable landscape requires minimum use of indirect solar inputs of energy, materials, and labor (Platt et al., [ed], 1994). Indigenous plants are cheaper and easier to suit the surroundings than the exotic ones (Greed & Roberts, 1998). They are well-suited for the local climate and easy to grow. Any virgin, untouched landscape in natural setting offers good bio-diversity models to learn from (Van der Ryn & Cowan, 1996). The quantity of the indigenous plants should occupy a dominant percentage in the whole residential landscaping.

1.2 Minimizing energy-resource consumption and labour input in landscape maintenance During the residential landscape maintenance, energy-resource consumption becomes a big problem and should be minimized. This can be achieved by careful selection of indigenous plants, imported wildlife species and proper landscape design layout. Local plants in their natural setting effectively need no manual labor, energy or resource input except the sun, and can grow well depending on their own species competition regime (Platt et al., [ed], 1994). Comparing with the hard pavement, vegetation covering can create natural habitats and per- mit better absorption of rainfall by natural means which implies cost savings in water management. Recent 20 years, ‘drought-resistant plants’ are popularized in America, for example use some beautiful drought-resistant shrub to replace the large irrigated grassland in order to save water (Makhzoumi & Pungetti, 1999).

“Wildflower meadows” is defined as diverse communities of native and naturalized forbs and grasses, and it can also enhance awareness of seasonal changes and expose surrounding vistas (Platt et al, [ed] 1994). It is considered that wildflower meadows are sustainable landscape. It

is also suggested that wildflower meadows should be prosperous in residential community (Van der Ryn & Cowan, 1996). To our thinking, wildflower meadow can be one of the methods to build up a sustainable landscape. Because it need few manual labor input, it can support more wild insects and wildlife habitats, and it can also express the original aesthetic of the plants themselves with no artificial factors. These are the benefits called economic, ecological and aesthetic. Wildness should be permitted with wise use in the sustainable development (Grumbine, 1994)

Recycling the water supply in the estate is another positive approach. There are three water resources in residential landscaping, including natural rainfall resource, underground water resource and manual irrigation. The natural rainfall resource can hardly supply the underground water because the hard pavement and man-made pipe in the estate. Therefore, the consideration of how to collect and apply the natural rainfall resource in the housing estate is very important.

1.3 Increasing biodiversity and micro eco-environment Ecological greenery provides good base conditions for biota to diversify and multiply. Bio- diversity allows a mixture of diversified plants and wildlife including insects and birds. In- serting and maintaining a high level of biodiversity in residential landscaping is necessary to create an authentic ecological environment (Greed & Roberts, 1998). Strengthen the relationship between water and plants can help to form a good eco-environment. The green spaces which consist of monotonous plant coverage play a lower eco-efficiency than the compound green space which made up of plants and waterbody. On one hand, water vapor may bring plenty nutrients to the plants surrounded and help them to grown more flourishing. On the other hand, plants can help to purify the water body. Therefore, water-growth plant type and waterside plant type should be encouraged in the residential landscaping in order to provide the possibility of forming micro eco-environment. Wetland is a good example. It is an ideal base for biodiversity and eco-environment and should be given plenty of consideration in the housing construction procedure.

1.4 Continuity of the greenery McHarg wrote in his book Design with Nature that the different scaled greenery system may bring a comfortable living environment and healthy micro-climate to the whole world (McHarg, 1969). In the past 20 century, many European cities are attempting to bring nature into the city-centre and to develop physical and ecological connections between built-up areas of the city and surrounding natural areas and greenspaces. Corridors and ecological connections can be found to various degrees in a number of these cities (Beatley, 2000). These ecological corridors intended to provide connections and migration opportunities between core areas. At the residential level, ensuring the continuity of the greenery may help to develop ecological corridors inside the estate and at the same time form a systematic greenery environment (Fang & Li, 2001).

1.5 Enhance the relationship between people and greenery In residential communities, ecological landscapes address not only environmental protection but also the interrelationship between people and nature. Landscape planning and design principles should promote ecological integrity while forming a balanced social and physical environment. Landscaping should help to form sustainable communities that offer opportunities for participation that encourage new modes of interaction among residents. Planners

cannot create sustainable communities without having the commitment from residents to modify or adapt their behavior or attitudes towards caring for the landscape around them. Residents may take part in the design process to express themselves in the surrounding environment; work together to take care of the landscape; or obtain knowledge about planting and ecology (Roe, 2000; Van der Ryn & Cowan, 1996; Grant et al., 1996).

2. Problems from Practice in Guangzhou, China China is now experiencing a high speed urbanization trend which accompanied with large-scaled real estate development especially in Canton. From 1990s, in Canton Pearl-River-Delta, urbanization has reached to 67% of the total area and real estate develop- ments have occupied large amount of it. Guangzhou, the center city of this region, is characterized by the new residential development expanding to the suburban area. The built area of Guangzhou has been enlarged by 1.8 times within these 20 years (Guangzhou Statistics Al- manac, 1991-2001). In the urban planning agenda of Guangzhou, the southern PanYu District which attached to the downtown area is planned to be developed into a residential region (Fig. 1). Already, a large-scaled and multi-leveled new residential district agglomeration has evolved there (Fig. 2). At the same time, because of the high population density, traffic jams and poor air quality, etc. in the downtown area, people are more willing to move to the suburban area.

During China’s high-speed housing development, the national construction department in Beijing has draft the 34% criterion of the “greenery-rate” for housing estate. Therefore the greenery-rate becomes a main goal in the housing development. In Guangzhou, large amounts of money have been invested in residential landscape construction, such as importing foreign plant species, paving large area of grassland in order to achieve high green-rate of the estate. For example, Yun-Jin Garden uses 5o million on its 30 thousand square meters residential landscapes. Many of them boast of “ecological estate” and “garden estate” with a high greenery-rate. Table 1 Greenery-rate in Guangzhou housing estate National Riverside South Star River Central Park Global Villa Criterion Garden Olympic View 34% 34.5% 35.51% 40% 43.6% 52%

Most of the estates in Guangzhou have exceeded the national greenery-rate criterion. The Central Park View housing estate which located in ZhuJiang new district even boasts that the green-coverage-rate in the estate has reached to 100% because of its distinguished roof gardens and “garden in the air”.

Fig.1 Diagrammatic map of Guangzhou and location of PanYu District

Real estates Fig.2 Residential estates distribution map of PanYu District

However, even with a high greenery-rate, some of the residential landscapes are in a low biodiversity (Yang 1997; Hao, et al. 2001; Ou, 2001). The concept of “how it looks” rather than “how it works” has dominated the current residential landscape design (Chen, et al. 2001; Ou, 2001; Liu, 2001; Hao, et al. 2001). Residential landscapes are mostly designed to visually please the residents but this approach results in high maintenance costs. This kind of anthro- pocentric landscape becomes very common now. At the same time, large energy consumption is also a big problem which includes labor input, fertilizer and water use, etc (Hao, et al. 2001; Han & Yang, 2001; Jia, 2001). Although Guangzhou has claimed itself as water-shortage free city, the whole country is still in the circumstance of shorting of water supply. Meanwhile, the water consumption amount of Guangzhou has now largely exceeded the national standard (Table 2). The water problem should be paid more attention to.

Table 2 Water consumption in China and Guangzhou National standard Housing design capacity in Actual consumption in Guangzhou Guangzhou 180-220 liter 300-350 liter 500 liter

3. Case evaluation and analysis Three cases are selected here for compare evaluation and analysis: Riverside Garden (810,000 m2), Global Villa (730,000 m2) and Star River (800,000 m2).

3.1 Applying indigenous plants Case 1: Riverside Garden Total land area of Riverside Garden is 810,000 square meter. Green coverage takes 275,000 square meters, i.e., 34% of the total land area. There are many different plant species, including bushes, wetland plants, bamboo and liana. There are a spatial variety and interrelated lay- ers of spaces. Open spaces are enriched by water body, groups of trees, passages and little hills (Table 3). Boast of its plentiful landscape environment, Kang-Cheng-Ju is selected as the case neighborhood here for evaluation and analysis (Fig.3).

Fig.3 Bird’s-eye View of Kang-Cheng-Ju Characterized a courtyard garden, Kang-cheng-ju outdoor space was designed based on Ling-Nan garden (a traditional southern China garden type) principles. The garden contains a small lake, water full manipulated by a recycling system, several small pavilion-like buildings, and 52 different kinds of trees, bushes and grass, providing a high potential of biodiversity. Almost all the plants are belong to the local species, such as Mei-ren-jiao (Canna gener-

alis Bailey), Da-ye-rong (Ficus virens Ait.var.sublanceolata (Miq.) Corner), and Mu-mian (Bombax ceiba L.). All of these bring a potential biodiversity environment.

Table 3 Plant categories statistics in Kang-Cheng-Ju Neighborhoods Arbor Categories Shrub Categories Land for greenery (m2) Kang-Cheng-Ju 20 31 13,770

Case 2: Global Villa Phase 1 and Phase 2 of Global Villa add up to 400,000 square meters, including 200, 000 square meters greenery. To-date the development continues with construction of Phase 3 which put on the market last August. Phase 3 is named Mountains & Water Garden which not only occupies 330, 000 square meters but also boasts a high level greenery area 190,000 square meters. The overall greenery rate of the estate reached to 52%. Table 4 Ecological Factors in Global Villa Item Quantity Residents average greenery area 29.7m2 per person Greenery rate 52% Co2 absorb 500 Ton per day o2 release 392 Ton per day Plant categories 277 Species Arbor and shrub species 500,000 Indigenous % 98%

In the aspect of importing foreign plants species, Global Villa boasts of its high-class status with eight Phoenix Canariensis which has an expensive price of 120,000 RMB per plant.

Case 3: Star River Founded in 2000, Star River Estate totally occupied 800,000 square meters. Up to date, it has a developed area of 460,000 square meters which including 180,000 square meters greenery. Phrase 1 consists of four neighborhoods – Langxin, Changxin, Yixin and Yixin. The largest Langxin community is selected as the case community in this paper (Fig. 4).

Fig.4 Landscape of Langxin neighborhood

In order to express a natural and tropical feeling, Star River uses hundreds of tropical and sub-tropical plants in its residential landscaping, for examples the majorities are Palmaceae and Ficus. These local categories are arranged with different levels and species in order to form a plentiful living environment for the residents. Besides these indigenous plants categories, Star River also imports several foreign species which has already been domesticated for purpose of increasing biodiversity of the estates. The plants species are: Phoenix Canariensis, Ceiba pentandra, Terminalia mantaly, etc. Phoenix Canariensis is still the most expensive plant here with the price around 100,000 RMB per item. The other plants are relatively less expensive with a price between 100 RMB ~ 200 RMB per item.

Discussion By comparison, it is found out that the estates in Guangzhou now have achieved some progress in popularizing the indigenous plants in residential landscaping. The quantity of indigenous plants has a dominate percentage in the landscaping. At the same time, properly importing foreign plants which has been domesticated can help to form a more plentiful environment. Phoenix Canariensis seems to be in great demand which stands for high class and honorable. However, the landscape price should be given more consideration to. The price of Phoenix Canariensis is really very expensive compared with other local species and is also difficult to maintain. The trend of pursuing luxury landscape should be changed.

3.2 Minimizing energy-resource consumption and labour input in landscape maintenance Case 1: Riverside Garden Take Kang-Cheng-Ju neighborhood as an example. Characterized a courtyard garden Kang-Yuan, Kang-Cheng-Ju has achieved some progress in its plentiful and variety plants species. However, the management company experienced some the technical complications, due to the various plants demanding different maintenance. The current labor distribution is shown in the below (Table 5):

Table 5 Labor distribution in Kang-Yuan Garden greenery management Item number Gardening 4 workers Cleaning 4 workers Managed area 5062 m2 per worker

The majority plants in Kang-Cheng-Ju are ever-green species and deciduous trees are minor part which only includes Da-Ye-Rong (Ficus lacor Buch) and Da-Hua-Zi-Wei (Lagerstroe- mia speciosa). Normally, the labour input in this area should be less intensive. But the fact is that it is difficult to meet residents and house owners’ demanding on a clean and tidy, modern style garden. For example, some residents complain of “bad management”, because they saw leaves or grass turning yellow in winter, which is actually natural with Da-Hua-Zi-Wei (Fig. 5 a). They refer to an adjacent neighborhood in which the large lawn with pointed trees in it is green all seasons. The lawn was an Australian species imported to China through Taiwan. It got a nickname as “Taiwan lawn” (Zoysia mafrella). To keep it green and clean, a set of rou- tine work is needed: providing fertilizer every 20 days, removing other species every 4 weeks, and cutting every month in summer. Management work is more labor intensive and costs are

higher (Fig. 5 b). It is certainly not ecologically sound. Therefore what’s the most important to avoid this circumstance is to change the residents’ attitude toward ecology.

(a) (b) Fig.5 Labor input in Kang-Yuan Garden

A major ecological setback is witnessed in landscape maintenance, in which tap-water was only water resource. According to national standard, every square meter of green lawn needs 2-4 liter of water per day. The current water rate in Guangzhou is 1.74RMB per cubic meter and considering 34% of land is green area in the estate, the total water cost of the estate is around 34,930 every year. The large lake in the middle of the estate was completely man-made and filled with tap-water twice, totally about 3000 cubit meter, since it was built in 1995 (Fig. 6). The problem has been addressed and solutions such as using water from adjacent river or from underground, has been investigated. However, they were not implemented because of the high costs of duplicating water supply system, complication of management, and also, the instability of river water quality. The under ground water contains high degree of salt and treatment was believed un-economical. Using recycled domestic gray water for gardening is gong to be implemented. In the newly built town house area, all greenery will be maintained with recycled water. Kang-Cheng-Ju has a low actual occupation ratio, around 30% of total stock. The recycled water is still not sufficient for gardening, although it is planned to be operated in the near future. A plan to use water from the lake nearby is under investigation.

Fig.6 The center lake of Riverside Garden

Case 2: Global Villa The Greenery Company of Global Villa is in charges of the following works: trimming, irrigation and spraying pesticide. The whole estate is divided into four zones and the management labour is distributed as the following (Table 6):

Table 6 Labor distribution in Global Villa greenery management Level (low – high) Item Arrangement Handyman Sweep floor, clean 3rd gardener Comprehensive work：trim, Arrange according to the real 2nd gardener spray pesticide, insects detection environment requirement 1st gardener Managed area : 3000~5000 m2 per worker In the aspect of applying fertilizer, on one hand, organic fertilizer is used in autumn and winter to maintain the nutrition. On the other hand, Carbamide and compound fertilizer are used in spring and summer to accelerate the plants growth. The total grassland area in Global Villa is 50,000 square meters and it need 2 cuttings per month in spring and summer period. And the total labor input is 12 workers. The whole greenery maintenance water in Global Villa is tap-water. Except the Golf Practice Court uses automatic irrigation, all the other places are manual irrigation. The total water cost of the estate is around 36,000 every year.

Global Villa is characterized for its famous water system Lago-Di-Com (Fig. 8). The whole water system in Global Villa is consisting of natural water, including the underground water from the surrounded mountain and the rainfall collection. In order to insure collection amount of the rainfall, the landscape water-block boundary design1 can be found all over the estate (Fig. 7).

Fig.7 landscape water-block boundary design Case 3: Star River In order to reduce the use of the pesticide and fertilizer, Star River has put some special con- siderations on plants species selection. For example, Ficus are the primary species in the residential landscaping because it is indigenous and fewer insects affected. What’s more, it can also bring a more sub-tropic feeling living environment. In order to save water, some water-resist plants such as cactus, Ying-Hai-Zao (Phoenix syloestris) are used in different neighborhoods.

1 It refers to constructing different leveled boundary block for the purpose of collecting rainfall. 10

Different with the natural water system in Global Villa, Star River is famous of the variable theme man-made waterbody all over in the estate (Fig.8). In order to match the water theme as well as reduce water cost, Star River set up its own water plant to recycle the water used in the whole estate in order to reduce the cost. The residents’ drink water is still from the gov- ernment while the water for the view and irrigation are from the recycled Pearl River water by its own water plant. Thus the water cost of the whole estate is relatively lower than the other estates. We may also notice many ecological designs for the benefit of recycling water. For example, cobble pavement drain off water design without artificial water leakage proof at bottom, so it directly attaches with the soil and underground water (Fig. 9).

Fig. 8 Water View in Star River Estate Fig. 9 Water recycling design of Star River

Discussion By comparison, the plentiful plants design in Riverside Garden is accompany with relatively high labor input and water consumption. The center lake and the whole irrigation water of Riverside Garden are lap-top water which means not only a high cost but also a waste of the natural recourses. Global Villa is successful in its water system planning which combine with the natural underground water and the rainfall water collection. The labor input intensive is relatively low; however the plants are not as plentiful as that in Riverside Garden and Star River. Star River can be viewed as another successful example in solving the water problem in the residential landscaping. The intentional design to collect and recycle the water makes the landscape to be more ecological. Large amount of local plants and water-resistant plants even help to save the water resources.

3.3 Increasing biodiversity and micro eco-environment Case 1: Riverside Garden Kang-Yuan Garden is centrally located and was made without artificial water leakage proof at bottom, so it directly attaches with the soil and underground water. Therefore it is more ecological and cheaper than conventional new gardens. Little fishes and insects of wetland were detected growing naturally. It indicates that a micro eco-environment is emerging (Fig. 10).

(a) (b)

Fig. 10 Eco-environment of Kang-Yuan Garden

Case 2: Global Villa The latest Phrase 3 Mountains & Water Garden is called “Forest Castle” because of the following two reasons. One is large amount of plants quantity in this neighborhood. The other is that because it is located at the highest place of the western part of Global Villa, surrounded by the mountain and forest as well as encircles the central water body which brings the best ecological eco-environment.

However, its slogan of “chief ecological estate” in Southern China, lots of the people feel that the supporting evidence is not enough. The whole inside landscape design didn’t express intentional purpose of the ecological meaning. “Ecology” is based on the whole residential landscaping of the estate and the good outside surroundings (Table 7).

Table 7 Internet survey of Mountain & Water Garden Survey item: being the “chief ecological estate” of China, you think the strongest support point is？ Item Vote number Landscape environment in the whole estate 82 Outside surroundings (ecological forest) 31 Estate environment plus surroundings 266 Above points are not obvious 231 （source：Global Villa Website http://www.gvhkcn.com/gvhk/research/resResult.jsp）

Case 3: Star River Langxin neighborhood is characterized with its plentiful riverside-plants types, such as Zhi-zhu-lan (Hymenocallis speciosa), Zong-zhu (Rhapis humilis), Chun-yu (Philodendron Selloum), Chui-liu (Salix babylonica), Hua-ye-liang-jiang (Alpinia zerumbet ‘Variegata’), Gui-bei-zhu (Monstera deliciosa), E-zhang-chai (Schefflera octophylla), Bai-ji-dan-hua (Plumeria rubra var ‘acutifolia’), Huang-xia-hua (Pachystachys lotea), Hong-ci-tou-lin (Pandanus veifchii) (Fig. 11 a). The whole water body in Star River is man-made water view. Although it has a close relationship with the surround plants, no eco-relationship is formed between them. Thus it is hardly to develop a micro eco-environment in the neighborhood (Fig. 11 b).

(a) (b) Fig. 11 riverside-plants in Star River Discussion Riverside Garden has successful approaches in design Kang-Yuan garden into a more ecological garden example in the real estate development. At the same time, Kang-Yuan garden is a good example of low budget and high benefit garden in Guangzhou (Table 8). A micro eco-environment is now forming in Kang-Cheng-Ju neighborhood. In comparison, Global Villa has more advantages in congenital good surroundings with ecological forest and Lichi garden. However the inside landscape environment does not match the “ecological” slogan. Global Villa can achieve more progress if it can improve its inside living environment in the future with a good surrounding base. Star River is full of water bodies while most of these are hard leakage proof bottom and separated from the natural ground water. It hasn’t formed an eco-environment yet. Future housing development may consider about the natural water body design in the future in order to increase the biodiversity and form a real eco-environment.

Table 8 Construction costs of Kang-Yuan garden (Yuan / m2) Kang-Yuan garden City gardens on average Highest garden cost in Tianhe District 500 1000 3000

3.4 Continuity of the greenery Case 1: Riverside Garden The landscape greenery in Riverside Garden is an entirety. The hollow railings are used as the partition for two neighborhoods instead of wall in order to keep the continuity of the greenery (Fig. 12 left). The landscape inside the neighborhood also shows a strong linkage between each other. Take Li-Zi-Lou as an example, it is composed of a hierarchy of courtyards: a central courtyard, small courtyards, interior courtyards, which are interconnected and traffic free (Fig. 12 right). It can not only provide a wide open space to the residents but also ensure the continuity of the landscapes.

Fig. 12 Greenery continuity in Riverside Garden

Case 2: Global Villa The greenery of Global Villa not only has a good continuity inside the estate but also well combined with the outside surroundings thus ensure the greenery continuity for the whole estate. The water system Lago-Di-Como is the key linkage of Global Villa. It provides the possibility of the variety biodiversity development (Fig. 13).

Fig.13 Site plan of Global Villa

Case 3: Star River Phrase 1, 2 are separated with Phrase 3 because of the South China expressway and the gov- ernment public road. In order to keep the continuity of the greenery of these 3 phrases, land-

scape was designed under the bridge which is a public governmental space. The variety plants not only rich the view under the bridge but also ensure the continuity of the landscape inside Star River (Fig.14).

Fig. 14 Greenery continuity of Star River

Discussion In order to keep the continuity of the greenery inside an estate, a clear planning idea should be formed at the very beginning. These three cases all have achieved some progress in greenery continuity. At the same time, some useful design approaches can also help to achieve this purpose whatever any problems suddenly emerged.

3.5 Enhance the relationship between people and greenery Riverside Garden has won numerous national and provincial prizes for her outstanding social activity and organization. In this aspect, Riverside Garden is chose as the only case to analyze the relationship between people and greenery. The resolution of United Nations Economic and Social Council states that participation requires the voluntary and democratic involve- ment of people in the following three aspects (Midgley et al., 1986) and this paper will try to compare the current approaches in Riverside Garden with them.

Contributing to the development effort is to see if the residents in the community contribute together with the rest of the community in the implementation of decisions. Though the inter- view to the estate developer, it is known that the idea of community participation has been set up from the very beginning. For example, for educational purposes, many trees are labeled with description boards providing botanical knowledge. Any new house owner is provided a chance to plant a tree inside the estate. The tree is labeled with the name of his or her child. (Fig.16) This activity aims to give the resident a chance to contribute to the whole development effort. At the same time, the management company to plant trees will organize all the residents in the residential area in every Arbor Day. People beautify their own living envi-

ronment and enjoy their own achievements and benefits. The community spirits is thus strengthened.

(a) (b) Fig. 16.Tree planter names are labeled together with botanical data.

Through the questionnaire to the residents, it is also found that 38% of the visited people say that they have never taken part in any activities. 75% residents said that they are interested in taking part in the activities but the main reason that why they haven’t done it is because they don’t got the chance. Therefore contributing to the development effort needs the wise leader- ship.

Sharing equitably in the benefits derived there from is to evaluate that if the residents in the community can derive equitable benefits from the programs initiated by the community leader. Residents are the masters of the community and they can be a designer to design and enjoy their own landscape environment; they should have the chance to give suggestions on how to transform the environment based on personal need or desire and therefore to share the benefits they arised for themselves. Riverside Garden is short of the consideration of how to ensure the residents to share the benefits they ought to have.

Decision-making in respect of setting goals, formulating policies and planning and imple- menting economic and social development programs is to see if the poorest groups in the community have an effective role in choosing social development programs. In Riverside Garden, residents can collectively monitor and supervise management work including landscape maintenance. The Owners’ Committee was found 1997 through an open process of consultation, nomination, and a poll, in which about 20% residents (5000 households) joint the polling. 13 members were elected and worked on voluntary base except one secretary (Table 9).

Table 9 Ownership Committee structure Position Number Director 1 person Associate director 1 person Property maintenance 4 persons Environment 4 persons Community culture 4 persons

In fact, the management company is employed and supervised by the owners’ committee. The owners’ committee has also provided a chance for the residents to take part in the decision-making or express their idea partly. However the represents of residents in the owners’ committee is still a minor part of the residents entirety and people can hardly get enough sov- ereignty and certain autonomy.

Discussion Community participation in the residential area should be populated from the basic common individuals - the residents, to the upper lead stratum- the developer and the designers. River- side Garden has applied some approaches to develop good community participation but actually this kind of participation is not real community participation. The policy maker is the management company and the developer. Residents can hardly take part in. The reason lies in the inherent problem of people’s consciousness. Promoting community participation needs to raise the level of social and political consciousness of local people. Many authorities have pointed out that community participation can be effectively initiated through the creation of specific projects that command popular support. For example, asking for suggestions at the beginning of a design process, and also ask for post-occupancy evaluation from the community residents.

4. Conclusion With the high speed urban development, people are getting further away from the nature. Green home becomes a dream of the modern society. Through the survey to the citizens, it is discovered that almost 100% people prefer to own more greenery in their living environment. An ecological, healthy surrounding may make people feel pleasant.

From the ecological point of view, residential landscape has several eco-functions such as adjust the micro-climate and release oxygen in the living environment. However, environmental problem now becomes more and more obvious in China because of the large-scaled housing development. The original natural topography and vegetation are neglected and de- stroyed during the human construction thus causes many ecological problems. Human should face the consequences they caused by themselves and try to solve the problems. An afford- able and comfortable housing environment in the 21st century should build up the harmony between human and nature.

Ecological landscape becomes a complex concept when applying the sustainable principles into the housing environment. Firstly, sustainability concerns about the energy input, labor input and waster output while not only the greenery areas. The natural vegetation requires low input while develops huge eco-benefits. Therefore the main idea of ecological landscape is to imbue natural eco-models into the man-made residential landscape in order to reduce the energy consumption as well as human labor input.

Secondly, the purpose of ecological landscape is to protect the local species and at the same time increase biodiversity. It cares about the quality of the landscape while not only the quantity. Residential landscape may become the best way to compensate the natural destruction during the large scaled housing development.

Thirdly, residential landscape is different from the urban public landscape because it has a close relationship with the local residents’ daily life. Therefore residential landscape requires

different design approaches to strengthen the interaction between residents and landscape and this can be realized in residents’ participation. Residential landscape becomes a media of the residents’ communication and conversely contributes to a harmonic neighborhood relationship.

In conclusion, the housing estates in Guangzhou now have achieved some progress in im- plementing ecological practices in their residential landscape planning. However, these kinds of practices have not been upgrade to a theory level. The origin of the problem lies in the consciousness of the whole society and the design process. Towards a more sustainable housing environment, ecological concept should be studied thoroughly from the very beginning of the development and design process.

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