Enchanted gardens come naturally

23 October 2017 | Research
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The natural forest garden beside Ventus allows students and researchers to learn more about nature (Photo: Zi En Jonathan YUE)

NUS Architecture Assistant Professor Hwang Yun Hye is on a mission to offer tropical cities like Singapore an alternative landscape management method of urban greenery — natural forest-like gardens that simulate an organic ecosystem, and stand in contrast to the heavily manicured lawns ubiquitous of the Garden City.

Asst Prof Hwang’s pilot project “From Lawn to Forest Garden” is one such example. A luscious garden that has hardly been touched in years, the project showcases a rare type of landscape in Singapore — the most urbanised city state in Southeast Asia — where the majority of urban greenery has been highly tamed by intensive maintenance regimes.

The research offers an alternative model of tropical urban greenery with a substantial level of ecological services achieved in a stressful urban context. It has the potential to motivate landscape policymakers and practitioners to implement similar projects across the island.

The study entailed fencing up a 2500sqm area beside the Ventus building on NUS’ Kent Ridge campus and leaving it to grow without human interaction for two years. Since then, the fences have been removed and minimal maintenance carried out such as weeding out aggressive plants to prevent overcrowding, removing a species that encourages mosquito breeding and protecting fruiting plants as a food source for fauna, while leaving most plants to grow spontaneously over time. A 70m boardwalk was later added as an outdoor laboratory space for students and researchers to develop an understanding of the complexities of urban ecosystems and connect with nature.

More than a pretty landscape, the garden also saw a rapid increase in biodiversity. Some 47 plant communities and 51 fauna species were recorded, up from an original 21 ground covers and 11 small insects. The new additions included groups of palms, ferns, shrubs, creepers and grasses as well as bees, butterflies, moths, birds and mammals. The garden has even become a stopover point for a pair of critically endangered spotted owls. 

Encouraged by the transformation, Asst Prof Hwang is working closely with NUS Facilities Management to implement the unique concept across the entire NUS campus in the near future.

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A pair of spotted owls classified as critically endangered in Singapore have been spotted in the garden (Photo: Zi En Jonathan YUE)

In another award-winning project, “Nature Refuge on Five Centimetres of Soil”, Asst Prof Hwang transformed an unutilised roof of a building at NUS Design and Environment (SDE) using a five centimetre depth of basic soil medium. With minimal maintenance — watering after five consecutive days without rain, selectively removing aggressive plants and trimming overgrown trees for safety — the green roof boasted 64 species of plants and 69 fauna species after a period of 18 months. The study offers an alternative type of extensive green roof in a high-density urban context where much of the green area on the ground is lost to competing uses, and which can be installed easily on most existing buildings.

Asst Prof Hwang’s projects have gone against conventional landscaping approaches. Although the tropics offer ideal conditions for spontaneous plant growth when maintenance activities are halted, traditional landscape management considers spontaneous vegetation as weeds to be removed. Furthermore, there is lack of a proper framework to integrate spontaneous species into landscape design, along with a presumption that less well-maintained vegetation will not be well received by the public. But the results from her projects speak volumes for the potential and benefits of leaving gardens to nature.

“The research offers an alternative model of tropical urban greenery with a substantial level of ecological services achieved in a stressful urban context. It has the potential to motivate landscape policymakers and practitioners to implement similar projects across the island,” said Asst Prof Hwang.

Asst Prof Hwang hopes her work will be used as a springboard to boosting biodiversity in the cities and is working with the National Parks Board to develop sustainable management guidelines for urban greenery in Singapore.  

Both projects were recently awarded the International Federation of Landscape Architects’ Award of Excellence in the Nature Conservation and Skyrise Greenery category respectively, accorded to landscape architects who have helped shape our environment towards a better future. She was also recently shortlisted for the prestigious Landscape Institute Awards 2017 for her green campus initiatives, with winners to be announced in November in London.

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A species of grass known as melinis repens flourishing on the SDE roof garden (Photo: Zi En Jonathan YUE)