Natural Coastline Defense: Mangrove Forests in Southeast Asia

Photo by Flickr user autan

Southeast Asia’s scientists, researchers, and political figures are emphasizing the importance of restoring mangrove forests, one of nature’s strongest defenses against natural disasters.

Mangrove forests offer a vast array of ecosystem services, or benefits to people, in tropical and subtropical coastline ecosystems. The massive root systems of mangrove forests mitigate the effect of strong surge storms on low-lying coastal communities by decreasing wave and wind velocity. According to the United Nations, “mangroves can absorb 70-90% of the energy of a normal wave.” By capturing rich sediments in their roots, mangroves also attract a variety and abundance of species such as shrimp, lobster, and oysters which can be harvested, sold, and eaten by local inhabitants. These forests also store carbon dioxide and aid in erosion control.

Despite all the benefits of an intact mangrove forests, parts of Southeast Asia have witnessed significant levels of deforestation. In Vietnam, the area of intact mangrove forests has decreased nearly 10,000 hectares (ha) since 1965. And the deforestation rate is on the rise. From 1965-1995, the rate was 0.2%, but from 1996 to present day, it is 13.1%. The cause of this sudden and explosive shift is due largely to land-use change, as shrimp farmers clear away forests to expand their prawn ponds.

Southeast Asia has been hit recently by several devastating natural disasters, including the Asia Tsunami (over 225,000 dead in eleven countries surrounding the Indian Ocean), cyclone Nargis (over 22,000 dead in Burma), Cyclone Orissa in India (1999) and Cyclone Sidr in Bangledesh (2007). According to the World Bank, Vietnam–with its 3200km of coastline–now ranks in the top 5 for countries that will be hardest hit by climate change. It is estimated that a five meter increase in sea level would flood 16% of Vietnam and threaten 35% of its population.

These recent natural disasters have made Vietnamese officials and citizens pay closer attention to mangrove maintenance. In 1994, the Vietnamese government began a cooperative project focused on planting new trees and maintaining existing mangrove forests, with the ultimate goal of protecting both the environment and the local population.

The effort is proving worthwhile. A recent WWF report found that although the Vietnamese government spent $1.1 million to plant 12,000ha of trees, they saved $7.3 million/year on sea dike maintenance. Additionally, the 2000 Wukong typhoon destroyed unprotected districts, but left regions protected by mangroves unharmed.

The restoration of mangrove forests has provided economic benefits for the population. One Vietnam News report revealed that intact mangrove forests created jobs for 3,210 households. Additionally, officials estimate that villages accrue a monetary benefit of US$2200-2500 per month due to forest protection and decreased maintenance on sea dikes.

Although Vietnam still suffers from significant mangrove deforestation, its restoration policy is headed in the right direction. Mangrove forests do not guarantee full protection from storm surges, but they do mitigate the effects of one of the region’s biggest threats. Therefore, it is in the best interest of the government and local population to restore and maintain nature’s natural storm barricades.

Emma Porteus is a WRI summer intern focused on researching and communicating messages about ecosystem services and how they relate to the public sector.