The Star Online > Lifefocus

Tuesday August 30, 2005

Harsh reality for tsunami-hit nations

By TAN CHENG LI

Scientists have, for years, shouted themselves hoarse about the wonder role that mangroves play in defending coastlines from erosive waves. Few heard them though, leading the world to lose half of its mangrove cover in the last 50 years to aquaculture ponds, coastal development and agriculture.

In the aftermath of the Asian tsunami, however, mangroves suddenly gained newfound respect among governments which once thought nothing about allowing the clearing of these coastal forests.

Tsunami-hit nations are now planting mangrove trees along coastlines to create “greenbelts” or vegetated strips of land, in the hope of preventing further erosion of damaged shores as well as to shield them from future giant waves.

The mass of tangled roots of mangrove trees is what makes this coastal forest so effective in buffering strong waves.

Some of these schemes, however, may prove futile.

In the dash to revegetate coastlines, ill-designed replanting projects have emerged. This concern was raised by scientists at a symposium organised by the International Society for Mangrove Ecosystems in Kuala Lumpur last week.

Dr Faizal Parish, director of the Global Environment Centre, observes that unsuitable tree species and planting sites, coupled with wrong planting techniques, have led to poor survival and growth of seedlings.

“With governments pressured into replanting, not enough study is being done to determine suitable sites and tree species,” he says.

In Aceh, Sumatra, where the worst coastal devastation occurred, Parish saw sites where mangrove seedlings were just shoved into the ground, and in open areas facing strong waves. As expected, many were washed away.

He says seedlings should have been grown in nurseries for three to four months to sprout roots and leaves before planting, to ensure better survival. He also saw seedlings planted in neat, straight rows – which offer little resistance to swift water flow. To do the job, trees should be randomly planted.

In one project in Aceh, Parish says Rizophora (bakau) seedlings were sourced from Java although good stands of this species exist on the east coast of Sumatra. It took 18 days for the seedlings to reach Aceh, by which time 60% had perished.

Most replanting schemes favour the Rizophora species – simply because seedlings are abundant and easily collected. But Rizophora may not be the right species to grow, according to forest ecologist Dr Noraini Mohd Tamin.

“They require sheltered sites but most of the damaged coasts are open and face the sea,” says the former Universiti Kebangsaan scientist who also found poor regeneration in several replanting sites that she visited in Banda Aceh.

The costly replanting mistakes of Aceh are being repeated in Malaysia. Parish and Noraini say seedlings planted in April in Kuala Muda, Kedah, where the tsunami had inflicted the most damage to the country, are not growing well and have low survival rates. The planting exercise costs RM60,000.

Like in Aceh, Rizophora seedlings were just pushed into the muddy earth, and in straight lines. “This works only if you are planting in the Matang mangrove (in Perak). This is a mature forest, so the bigger trees will shelter the seedlings,” explains Noraini.

“Kuala Muda is an exposed site. So seedlings are smothered by beach deposits and are easily dislodged as they lack roots. Mangroves grow best in protected estuaries and bays.”

Students helping to plant mangrove seedlings in Balik Pulau, Penang, in March.

Noraini notes that people are cashing in on the demand for Rizophora seedlings. Prices have hiked from 50 sen each last year to RM3. She says the Avicennia mangrove species are more suited to exposed coasts but they are hardly used for replanting because seedlings are not easily available since this species does not fruit year-round. In fact, Avicennia trees would be more suitable for Kuala Muda since they grew there originally. Villagers had, over the years, felled the trees as well as Nipah palms found there.

“Everyone wants to be seen doing something after the tsunami. But if the planting is not planned and done properly, some seedlings will not grow,” says Noraini.

In erosion-prone coasts, she says replanting must be combined with installation of wave breakers. Otherwise, seedlings will be swept to sea.

Post-tsunami replanting in Balik Pulau, Penang, also suffers from poor seedling growth, says mangrove scientist Dr Ong Jin Eong.

“For effective rehabilitation, you must plant the correct species, understand the hydrodynamics of the place and determine the site,” says the retired Universiti Sains Malaysia lecturer. “Scientific studies on the functional physical and ecological processes involved must be carried out before more good money is poured into badly thought out so-called mitigation projects.”

Ong believes money will be better spent saving an intact forest rather than rehabilitating a degraded one. “You can never recreate the original. This is expensive and you don’t get what you want.”

Tan Kim Hooi, senior researcher at the Maritime Institute of Malaysia, concurs.

As replanting projects are risky and involve taxpayers’ money, he says there should be proper assessment and planning.

He says many replanting projects with Rizophora apiculata and Rizophora mucronata in exposed coastlines in Asia have failed. In fact, both species are not commonly found in the natural environment of Penang and Kedah coastlines and yet, are being used in coastal rehabilitation efforts.

“We are living in the shadow of Matang’s success. The planting of R. apiculata there has been so successful that people think we can plant this species anywhere along the coast,” says Tan. On the contrary, both Rizophora species can tolerate only a narrow range of environmental conditions – specifically estuarine areas with brackish water and heavy rainfall. Matang has these conditions but not the coastlines.

Tan also questions the need to replant. “The immediate action should be to protect existing stateland mangroves which are about 100,000ha and subjected to various development threats. There is no point replanting while at the same time, we are losing these stateland mangroves.”

Planted in neat rows in the highly exposed coast of Kuala Muda, Kedah, these mangrove seedings are unlikely to survive strong waves that pummel the shore.

Indeed, with mangroves being a rarity – they cover a mere 0.04% of Earth’s surface and 0.12% of its land area – we should conserve whatever mangrove that remains. This is cheaper too.

In Malaysia, it costs RM15,000 to replant one hectare of mangroves. The government has identified 4,016ha of degraded mangroves requiring rehabilitation at a cost of RM110mil. Some 151ha have been replanted so far.

Ultimately in the long-term, Parish says nations have to review their coastal development plans to include a “zero development” zone of 200m to 500m width, and turn it into a greenbelt consisting of mangroves, casuarina trees or mixed crops.

Many tsunami-hit countries are finally implementing such rules, which existed but were never enforced.

“The tsunami was a wake-up call for many,” he says.

But there is no quick fix. Parish points out that a stable greenbelt can form only in five to 10 years. “So we need sustaining action. That means designing a long-term programme now.”

In the rush to maintain and create greenbelts, however, the role of other coastal ecosystems in shielding shorelines should not be ignored.

Dr Sundari Ramakrishna, director of Wetlands International Malaysia Programme, asserts that coastal peatlands, beach dunes, coral reefs, mud flats, seagrass beds and tidal flats can also do the job.

These habitats deserve attention and protection too.

Impact of the tsunami The Dec 26 tsunami left behind extensive environmental damage across the region. It totally changed coastal landscapes and ecosystems. The impact include: Loss and degradation of mangrove and seagrass beds Silting and degradation of coral reefs Change in tidal flats and coastal lagoons Uplifting of the seafloor in some areas Turbid coastal water Scouring of coastline Inland deposition of sand Salination of coastal land Impact on fisheries The role of mangroves during the tsunami Reflect and resist tsunami energy, thus reducing the inundation depth and area. Trap driftwood and other debris, thus reducing human injuries and property damage. Prevent people from being washed out to sea. Reduce erosion of beaches and sand dunes which also act as barriers to tsunamis.