[NEW DELHI] Large-scale destruction of mangroves contributed heavily to the damage inflicted by cyclone Nargis in Myanmar last week, says the UN Food and Agriculture Organization (FAO).
Myanmar, home to the eighth largest mangrove area in the world, has lost large swathes of mangroves over the last four decades. FAO estimates from 2005 put the loss at around 70,000 hectares between 1972 and 2005, but 2008 estimates suggest this could be much higher.
Losses have been particularly substantial in the Irrawaddy delta, the country's largest mangrove area, where cyclone Nargis struck (see Ignored warnings 'worsened' Myanmar cyclone disaster).
At barely 100,000 hectares the delta has lost half its mangrove area since 1975, Mette Løyche Wilkie, senior forestry officer at the FAO forest assessment and reporting service, FAO, told SciDev.Net.
Mangrove destruction has also occurred in Rakhine and Tanintharyi regions in western Myanmar, but to a lesser extent due to lower human pressure on these areas.
The Myanmar mangroves were destroyed for conversion into rice fields, large-scale shrimp and prawn farming introduced in 1995, extraction of fuelwood and charcoal for Yangon — the country's largest city — and expansion of human settlements.
According to Jan Heino, assistant director general of FAO's forestry department,
"Settlements have been established closer to the sea and the combination of proximity to coastal hazards and lack of a protective forest buffer has increased the risks to human populations in many countries, including Myanmar."
Wilkie says coastal forests can protect against currents and waves associated with cyclone storm surges even if they cannot prevent flooding.
In dense mangroves, the tree's trunks, branches and roots offer resistance to the force of waves and reduce the impact. Mangroves also trap and stabilise sediments and reduce the risk of shoreline erosion, while ground vegetation can protect against smaller waves.
According to the FAO, during cyclone Sidr, which struck southern Bangladesh in November 2007, the Sunderbans mangrove forests played a crucial role in mitigating some of the cyclone effects.
And the Indian Ocean tsunami of December 2004 highlighted the importance of mangroves and coral reefs in reducing the impact of such disasters, as areas in Sri Lanka with mangroves suffered less damage than those without mangroves.
Coastal planning to ensure a protective buffer zone where habitation is discouraged is one way to reduce damage from future cyclones, says the FAO.
Other methods include early warning systems, evacuation plans, effective communication and transport infrastructure, and storm shelters.