Mangroves are best defence against cyclones: researcher

Jatindra Dash, Indo-Asian News Service, Hindustan Times 5 Nov 07

Mangroves are a natural defence against cyclones and would have helped prevent many of the deaths in the 1999 super cyclone besides having several economic uses as well, says a Delhi University researcher urging that such forests be re-established.

According to Saudamini Das, a researcher and economics lecturer at the Swami Shradhanand College of Delhi University, "if we leave a hectare of mangrove forests intact, then the value we get from it is twice of what we would get if we cleared and sold the site for building houses or hotels."

The super cyclone of October 1999 claimed the lives of almost 10,000 people as well as 400,000 livestock. Almost two million houses and over 1.8 million hectares of crop were destroyed in 12 of the state's 30 districts.

Das re-constructed the situation in coastal Kendrapada district, about 150 kms from Bhubaneswar, in order to get a true picture of the importance of mangroves in protection from storms.

She says fewer lives would have been lost in the super cyclone if much of the mangrove forests had not been cut down.

In 1950, 80 per cent of the district's coastline was covered with over 300 sq km of mangroves, which had a width of nearly 10 km.

However, at the time of the cyclone, mangroves covered only 50 per cent of the coastline. It was noticed that areas protected by mangroves suffered fewer losses than other parts of the district.

Mangroves trap sediment in their roots, creating shallow shorelines that slow oncoming waves and dissipate wave surge. Their leafy canopies shelter land from high cyclonic winds. Although widely recognised, these protective functions have not been well researched. Even less is known about the extent of the economic benefits provided by these functions.

The super cyclone had its landfall 20 kms southwest of Kendrapada and the entire district was battered by cyclonic wind and rain.

If the mangrove forests that had existed in 1950 were still in place, only 31 people would have died in the district as opposed to 392 who actually lost their lives in the 1999 disaster, according to findings of the study sponsored by the South Asian Network for Development and Environmental Economics (SANDEE).

"If the present mangrove forests hadn't been there at all, the death toll would have been 54 per cent higher than it actually was - an additional 211 people would have died," she said.

Vast stretches of mangroves have been lost due to degradation, coastal development and shrimp farming.

"Kendrapada, which is poor and a predominantly agricultural region, has seen significant loss of mangroves in the last half century like other coastal regions of the state," she said.

In addition to offering protection from cyclones, mangroves provide other benefits too - they are a source of firewood and forest products to local communities and act as breeding places for fish.

Saudamini's study has found that a hectare of mangrove forestland could have prevented damage worth Rs 1.8 million in the area she studied during the super cyclone.

Since severe storms don't occur all the time, she multiplied this number by the probability of occurrence of severe storms in Orissa over the last three decades to estimate the value of mangroves.

"Based on this, the value of a hectare of land with intact mangrove forests is Rs 360,000. Currently, a hectare of land after mangroves are cleared sells at Rs 200,000 in the market," she said.