Architects want houses to grow rooftop trees in Vietnam's ‘suffocating’ cities   A man walks on a grass garden on the roof of a hotel in Hanoi. Photo: Le Quan As urban development has taken over most public green places in Vietnamese cities, architects suggest moving trees to rooftops. The new Asian Green City Index compiled by the Economist Intelligence Unit shows Hanoi and Ho Chi Minh City falling far behind other Asian cities in terms of availability of green spaces. Hanoi’s green space per person is one square meter, compared with 105.3 sq.m in Hong Kong, 60 sq.m in Singapore and nearly 44 sq.m in Kuala Lumpur. But the capital is doing better than Ho Chi Minh City, which only has 0.7 sq.m. The southern city plans to increase this, but to just 4 sq.m in downtown areas and 17 sq.m on the outskirts by 2020, still far below the current world average of 39 sq.m. Outlying districts in HCMC, which still have a lot of vacant lands, tend to give them to property developers, while major downtown parks that are dozens of years old have lost parts to urban development projects like bus stops, theaters, restaurants, and housing. Authorities in both Hanoi and HCMC have chopped down hundreds of trees since late last year to make way for the country’s first metro routes and other major infrastructure projects. Architects said if the cities can no longer offer space for trees, people can use their houses, growing them on their walls and roofs. Mai The Nguyen, a Vietnamese-Norwegian now living in Hanoi, said green houses with trees around them are becoming a global trend. The Norway government recently required half of the houses in a downtown Oslo area to plant grass on the roof, he said. Countries in Vietnam’s neighborhood such as Singapore and Malaysia are also introducing similar policies. “The trend is precipitating into a revolution worldwide. People are planting grass, vegetables and even orchards on their rooftops,” Nguyen said. He said the gardens also help retain 50 percent of rain water, reducing the drainage burden, and have insulation effects. Architect Vo Trong Nghia, who has won various international awards for his green designs, said Vietnamese cities have become “suffocating” and green houses should become legally obligatory. For example, the authorities should only grant construction permits if the house owners promise to put trees on their roofs, he said. “If we start now, Hanoi and Ho Chi Minh City will be very green and beautiful in around three years.” By Dinh Son, Thanh Nien News