A majority of the flora in the area was killed by defoliants sprayed by the U.S. Air Force during the Vietnam War.Today, the replanted forest protects the city from storms, and stores huge amounts of carbon dioxide, though development plans and aquaculture pose threats to Can Gio’s continued health. HO CHI MINH CITY, Vietnam — As the largest urban area in Vietnam, Ho Chi Minh City is known for its kinetic pace of life, rivers of motorbike traffic, and relentless construction. With an official population of 9 million and a booming economy based on manufacturing, real estate and tourism, there is often little space for nature. It may come as a surprise, even to many who live in Ho Chi Minh City, that one of the world’s great restored mangroves forests lies within the city’s borders. The Can Gio Mangrove Biosphere Reserve covers 75,740 hectares (187,160 acres), and encompasses all of Can Gio district, the largest and one of the least populated of Ho Chi Minh City’s 24 districts. Can Gio sits between the central districts and the South China Sea, called the East Sea by Vietnam. From above, it’s a surprisingly green stretch of land, especially compared to the gray tentacles of concrete that spread out farther from the city every day. Inscribed as a UNESCO Biosphere Reserve in 2000, Can Gio includes a 4,721-hectare (11,666-acre) core area where human activity is strictly prohibited, a 41,139-hectare (101,657-acre) buffer zone where cultural and ecological development is allowed, and a 29,880-hectare (73,835-acre) transition zone where normal socio-economic development occurs. The area is currently only connected to the rest of Ho Chi Minh City by ferry, though a major bridge has been approved. On the coast, tourism development is growing, in line with Vietnam’s increasingly wealthy middle class. Such construction will pose risks to the health of Can Gio’s mangroves in the future, but it’s something of a miracle that these forests exist at all.