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Spring 2009

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Garden City-State Maintains 1.3 Million Trees

Singapore Manages Urban Forests Using GIS


  • National Parks Board catalogs 1.3 million trees and shrubs with server GIS.
  • Multiple government agencies share geospatial data through a custom GIS application.
  • A mobile GIS data collection process saves time and streamlines the tree cataloging process.

Envision a 263-square-mile island city-state that is one of the world's busiest seaports, a major oil refining and distribution center, a leader in shipbuilding and repair, an aggressive supplier of electronic components, and home to more than four million residents. It sounds hectic, but it's more relaxing when you imagine that the same island has more than 36 square miles of parks, open spaces, nature reserves, roadside greenery, and vacant lands and 16 additional square miles reserved for parkland when the population reaches 5.5 million. You are imagining the island country of Singapore, known to many as the Garden City.

  click to enlarge
For each tree pictured on the PRIME interface, NParks stores additional information about its size, species, health, and trimming history.

Singapore has not always been known as the Garden City. In 1963, Prime Minister Lee Kuan Yew recognized the importance of greenery as a factor in attracting foreign investors, so he launched a tree-planting campaign. However, the investors came faster than the trees, resulting in a modern landscape that was heavy on development and light on vegetation, until 1976 when the Parks and Recreation Department was formed and tasked with aggressively planting trees and shrubs around the island. Simultaneously, the Ministry of National Development initiated road codes, which mandated that adequate planting areas be provided along new roads. An islandwide parks program led to the improvement and creation of national parks, and developers of residential areas were required to plant roadside trees and set aside land for open space. By the mid-eighties, Angsana, rain tree, yellow flame, and mahogany trees and vines—such as bougainvilleas and Ficus pumila—provided visual relief from expanding structural development, turning Singapore into the Garden City that Prime Minister Yew envisioned.

In the 21st century, Singapore has continued its aggressive planting practices, and just as its electronics industry has flourished with new technology, so have its methods for identifying, cataloging, and inspecting trees. The Singapore National Parks Board (NParks) supervises 1.3 million trees located in 300 parks and on more than 2,400 hectares of Garden City roadsides using GIS. NPark's GIS, known as the Park Integrated Management System (PRIME), is a custom software application built and hosted on an ArcGIS Server platform. ArcGIS Server was chosen because, for more than a decade, NParks and other government agencies in Singapore have shared information through a common GIS called the Land Information Network (LandNet), also supported by ArcGIS.

LandNet hosts an island basemap containing layers such as roads; buildings; waterlines; parks; and, of course, trees. Updates in the tree layer of PRIME go directly to LandNet; thus, any tree data imported into PRIME becomes visible in the LandNet environment. Through LandNet, the Land Authority, Singapore's Land Transport Authority, and Urban Redevelopment Authority access NPark's tree data regularly. For safety reasons and as reference to help preserve trees in the construction of new roads, as well as in the widening of existing roads, it is crucial that the Land Transport Authority knows where each tree is located along Singapore's roads and railway infrastructure. It is also useful for the Urban Redevelopment Authority to know where trees are located when planning new housing or business developments. This information can be accessed and viewed from desktop computers, or it can be used to produce paper maps.

ArcGIS Server technology also supports mobile computers, which NParks uses in the field to record its tree data. NParks' field crews use handheld computers equipped with ArcPad to log data related to the position, size, health, and species of each tree. Once data is entered, the GIS integrates with the database to generate and assign a unique ID to each tree and stores it in the PRIME geodatabase. NParks began using GIS to capture tree locations in early 2000, and currently, most of the roadway trees and trees in the abutting open spaces have been recorded. A smaller percentage of national parks trees have been cataloged in the PRIME geodatabase due to other constraints.

"The previous method for cataloging trees was a very manual process," says Tee Swee Ping, NPark's assistant director of Streetscape. "It involved a tedious manual ID system and a lot of paperwork. GIS is much faster and more efficient and provides better documentation. It is very neat, clean, streamlined, and standardized."

  photo of Orchard Road
Singapore's busy Orchard Road is well known for its traffic, shopping, and trees.

In addition to importing data on location, size, and species, for legal purposes, a health inspection is conducted regularly and recorded each time a tree is trimmed. Tee says that having information about the inspection and pruning history of a tree is documented proof that NParks is giving due care to its trees. Between NParks' employees who prune trees on the roadway and in the parks, the employees who develop new parks, and those who concentrate on how the development of land will impact existing trees, there are more than 150 workers dedicated to caring for NParks' trees.

As urbanization has continued to spread throughout Singapore, so have efforts to keep the island rich in vegetation. Developers are required to replace or replant for every tree uprooted during construction, and the road codes for planting along new roadsides are still enforced. New parks continue to be developed and populated with tree shade, and government and public programs—such as Heritage Tree Scheme, Heritage Roads, Community in Bloom, and Plant-A-Tree—promote a good balance of industry and nature. Recording Singapore's trees in a GIS helps NParks and other government agencies assure that these policies, guidelines, programs, and stipulations are followed.

"Quite a number of people have suggested that we implant a chip in every tree that could be read by GPS," says Tee. "What is the added advantage of that? I already have my GIS with different views and layers inside. Our goal is to get a physical description and the position of each tree in relation to other objects, and our GIS does that. We have our roadway layer in our GIS. We have our lamppost layer in our GIS. We have our tree layer in our GIS. We have good GIS basemaps, and when you add all those layers, you can visualize everything in perspective and accurately."

More Information

For more information, contact Tee Swee Ping, assistant director of Streetscape, National Parks Board, Singapore (e-mail:

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