Landscape Architects of Bangkok has reforested a speck of the Thai capital. The cobras seem to approve.

By James Trulove / Photography by Rungkit Charoenwat

It would not be a stretch to think of this reforestation project as a “vest-pocket” park, much in the tradition of the work of the noted landscape architect Robert Zion in New York City. After all, the name of the project, “Metro-Forest,” might suggest as much. Though it is not bounded on all sides by encroaching office towers, this five-acre landscape rests squarely in the midst of equally inhospitable and unchecked suburban sprawl dotted by illegal dump sites (of which this was once one), a tangle of expressways and surface roads, and the din of more than 800 planes landing and departing nearby every day at Suvarnabhumi Airport, which serves Bangkok. Certainly many of the design elements of a vest-pocket park are present: a water feature to mask the clamor of planes and cars, native plants that recall a bygone era, seating to contemplate the surrounding nature, hardscape to create boundaries, and a carefully designed network of berms that increase the overall planting area of this small space while blocking views of the surroundings.

The project, which won a 2016 ASLA Professional Honor Award for General Design, is an oasis, but also much more. It has also become an important laboratory for exploring ways to create a diverse forest ecology. It employs planting techniques developed by the noted Japanese botanist Akira Miyawaki and implemented here by the designers at Landscape Architects of Bangkok (LAB) under the direction of one of Miyawaki’s students, Sirin Kaewlaierd. The so-called Miyawaki method is a proven, straightforward approach to reforestation: Seedlings native to the area are densely planted on a site. As the seedlings compete for nutrients and water, the strongest survive and flourish, and within three years the forest is on its way to maturity.

The project brief describes the Metro-Forest as “an ecological regeneration project” on an abandoned landfill site. It is conceived as an exhibition space to educate people about the ecology of the local forest, which consists of tropical lowland. The plantings, both native and introduced, aim to “reverse the trends of suburban sprawl,” particularly heat-island effects and flood proneness. Saplings of many of the trees planted here were prominent around Bangkok during the mid-19th century. Many districts in the area are named after them.

Finding this forest in the thicket of suburban Bangkok sprawl is not easy. No signs mark its existence until you arrive on the site. I arrived in a passenger van that came upon an overpass it was too tall to clear. The van backed up and followed a more circuitous route along surface roads. When we finally arrived at the Metro-Forest, we were greeted at the entrance gate by a crowing rooster, guarding his turf, as it were. Several chickens roam the site, placed there by the client, PTT Public Company Limited, the state-owned oil and gas company of Thailand, perhaps to create a more agrarian atmosphere. (The site is managed by PTT’s Reforestation Institute, which works on sustainable conservation of natural resources throughout Thailand.)

Besides the rooster, there is a small guard station at the entrance. When the Metro-Forest first opened, visitors were required to have made reservations in advance, though, owing to its popularity, that requirement has been dropped.

It was expected that 100 visitors a day at most would tour the site, but as word has spread, weekends have brought as many as 1,500 people. Tawatchai Kobkaikit, ASLA, a lead designer on the project as managing director of LAB, says that neighbors from surrounding housing stop by to enjoy the sunset from the skywalk that encircles the forest at considerable heights.

At the entrance to the site, a broad fire lane leads past an inadequate parking lot that can hold only 12 cars and continues around the perimeter of the forest. The parking lot is now a storage site for exhibition materials, so all visitors have to park along the public access road.

The formal entrance to the forest is along a rust-colored concrete walkway that leads to an exhibition center. The center is carefully tucked into the site, disguised by a green roof and massive rust-colored walls of rammed earth. Kobkaikit notes that the building, by Spacetime Architects, a Thai firm, is among the first projects in Thailand to use rammed earth, and it has inspired other Thai architects to experiment with the technique. To reach the exhibit halls, you enter a narrow corridor created by two curving, parallel rammed-earth walls that are 20 feet high and open to the sky. Walking down this corridor, I was quickly reminded of the work of the sculptor Richard Serra and his site-specific rust-colored steel walls that embrace and dwarf you as you move into them. You could say that this experience of compression prepares visitors for the drama of the forest they are about to experience. The rammed earth, trucked up from the southern Rayong Province, was chosen as the building medium as a way of emphasizing the importance of soil for this project. Placed along this corridor, as part of Metro-Forest’s educational program, are kiosks that contain samples of some of the seeds used to plant the forest.

The PTT Public Company wanted LAB to create a self-contained environment that would allow people to become immersed in the landscape. To this end, a series of large earthen berms was created, some as high as 13 feet, both to shield views of the surrounding suburban chaos and to provide a carefully engineered soil mixture that would facilitate the growth of the 60,000 trees (mostly seedlings), representing more than 279 species. During a tour of the forest, Kobkaikit repeatedly emphasized the importance of the soil used to create the berms, as prescribed by Miyawaki, to create an optimal planting environment. When the project began in 2013, 48,000 cubic yards of earthwork was brought to the site and mixed with an additional 7,800 cubic yards of planting medium to create the berms. The resulting berms also led “to the creation of diverse microecologies” throughout the forest, Kobkaikit says.

Given that the project is essentially constructed in a swamp filled with brackish water, plants were selected that thrive in this water and planted along the embankment created by the berms. Similarly, a diverse mix of deciduous forest plants and lowland dipterocarp cover the area along the riparian edge, atop the berms.

The exhibition center is divided into two halls, the first with displays focused on the value of ecology. The second is a theater that was screening a short film designed to appeal to young students on the value of planting trees. After the film ends, the large screen, divided into vertical panels, pivots open, dramatically revealing the forest and the skywalk. A quick jog across the lawn leads to the beginning of the skywalk that quickly ascends above the tree canopy and follows a zigzag path around the perimeter and then into the core of the forest. The 600-foot-long skywalk was mandated by the client but initially opposed by the landscape architects, and yet it has turned out to be a very important design element on two fronts. First, because of the rapid and spectacular growth of the forest, visitors ascending the skywalk find themselves moving through and above the tree canopy while leaving undisturbed the undergrowth of the forest. A second, more practical consideration has emerged supporting the need for the skywalk: cobras. The district in which the forest is located is known in Thai as Nong Ngu Hao, which translates as “cobra swamp.” Needless to say, a walk along the ground floor of the forest could become an Indiana Jones-like adventure. And then there are the occasional monitor lizards to further balance what is becoming a sustainable landscape.

As you ascend higher on the skywalk and ultimately above the tree canopy, the illusion of being lost in a forest is quickly dashed. In the immediate foreground just beyond the forest’s boundaries, the illegal dumping site that was once the Metro-Forest has simply moved on to adjacent plots of abandoned land. And in the distance to the east, silhouetted in a haze of smog, are the office and residential towers of Bangkok. Some four miles to the west is the control tower of Suvarnabhumi Airport, seemingly animated by the heat waves in the scorchingly hot and humid Thai climate.

Not to be outdone, the Metro-Forest has its own tower (also mandated by the client) that is accessible from the skywalk. Here the energetic can climb an additional 65 feet or so to fully appreciate the uniqueness of the Metro-Forest within the context of its surroundings. According to Kobkaikit, a height restriction was placed on the tower owing to its proximity to the airport. From here, the notion that you are indeed immersed in a laboratory becomes dramatically apparent. Looking down on the forest, the design of the Metro-Forest microcosmos fully asserts itself. The closed circulation, the designed waterfall and stream that meanders through the forest, has literally taken on a life of its own and requires no liner to sustain the water levels. It is replenished by groundwater and rainwater. Sounds from the robust waterfall reassure you that nature is not far away. From the tower, the skywalk dips down to the forest floor and a small footbridge crosses the stream, and a path leads you back to the exhibition center. Given the concerns regarding the cobras, an elevated walkway in this area is under consideration. As you leave the forest, the rooster is still at his post. For now.

James Trulove is a publisher and editor of books on architecture and landscape architecture.

 Project Credits

Client PTT Public Company Limited, Managed by PTT Reforestation Institute, Bangkok. Landscape Architect Landscape Architects of Bangkok Ltd. Architect and Interior Design Spacetime Architects Co., Ltd. Mini-Theater Interior Design designLAB NLSS Co., Ltd. Ecological Forest Consultant Sirin Kaewlaierd. Landscape Design Consultant Angsana Boonyobhas. Energy and Green Building Consultant Architects 49 Limited. Quantity Surveyor Langdon & Seah (Thailand). Construction Management EDA Consultant Co., Ltd. Commissioning Authority SCG Green Building Department. Exhibition Design Pico (Thailand) Public Company Limited. Lighting Consultant 49 Lighting Design Consultants Limited. Structural Engineering H Engineer Co., Ltd. MEP Engineering MITR Technical Consultant Co., Ltd. Main Contractor Ritta Co., Ltd. Softscape Contractor Cordia Company Limited. Waterfall Contractor Tropical Garden Ltd., Part. Rammed Earth Subcontractor La Terre Co., Ltd. Earthwork Contractor Psatanachod Kanyotha Co., Ltd. [NOTE: ALL ARE LOCATED IN OR AROUND BANGKOK.]