Singapore’s super trees
When dusk falls in Singapore, an elaborately choreographed 15-minute light and sound show called the Garden Rhapsody begins. It happens at Gardens by the Bay, a 100 hectare park that opened in 2012. Its protagonists are 18 super trees: tree-shaped metal towers 25 to 50 meters in height on which grow more than 700 species of bromeliads, orchids, ferns, and creepers. Eleven of the super trees perform other tasks as well. Some have photovoltaic cells in their canopies to generate energy for the light show. Others serve as ventilation shafts for greenhouses below. The trees also collect rainwater to irrigate the plants, and the tallest has an observation deck. In its most recent fiscal year (2019-2020) Gardens by the Bay attracted 13 million visitors.
Barcelona has about 1.6 million residents. On weekdays, its streets used to be clogged with 1 million vehicles. That, it decided, was too many. It responded by creating “superilles” or “superblocks,” aggregations of four to nine city blocks in which traffic is largely banned (only residents’ cars and delivery vans are allowed and they must travel at a walking pace). The program was initiated by Ada Colau, who was elected mayor in 2015. She assembled a team of environmentally conscious policymakers and urban planners to reclaim public space from cars. The result was the first superblock, created in 2017 in El Poblenou, a hip waterfront neighborhood. There are now six superblocks and there could eventually be hundreds more. The reclaimed space has been put to creative use: formerly busy intersections have been replaced by public gardens and playgrounds. The program is accompanied by measures to encourage the use of public transport. The city has added 28 bus lines and organized their routes so that no resident has to walk more than 250 meters to the nearest bus stop. It also plans to triple its network of bike paths to 300 kilometers by 2030.
What have the superblocks accomplished?
The superblock in El Poblenou, according to an analysis by weekly German news magazine Der Spiegel, now has almost no vehicle traffic. The city itself says that traffic has declined by 80% to 90% in one of the superblocks yet has increased by no more than 5% on perimeter streets. In addition, the heat island effect has become less intense. The superblocks will also likely improve Barcelona’s air quality. A study by the Barcelona Institute for Global Health predicts that the superblocks will enable the city to reduce its nitrogen dioxide levels from 47 micrograms per cubic meter to 36 micrograms (the WHO threshold is 40 micrograms). The study also says that Barcelona’s greenhouse-gas emissions could be 40% lower by 2030. Finally, the superblocks will increase the area of green space per inhabitant from 2.7 to 3.7 square meters. Although still below the WHO’s recommendation (9 square meters), it will be a significant improvement.