It's clear that the elimination of mangrove forests along Southeast Asian coastlines made the impact of the December 26 tsunami even worse. But we're now seeing signs that it's not just mangrove forests which can reduce the effect of flood surges -- casuarina and eucalyptus trees work well, too:
On Dec. 26, as the killer tsunami struck down thousands of people and homes in Tamil Nadu state, the casuarina and eucalyptus trees which had been planted to appease the weather gods saved the lush green village of Naluvedapathy.
The casuarina trees, which numbered more than 60,000, took the brunt of the tsunami waves as they swept Naluvedapathy.
The giant waves inundated dozens of thatched-roof houses in the village as they swept inland [...] But the casuarina trees had considerably weakened the waves and reduced the impact, villagers said.
Tamil Nadu government officials are now assembling a trust fund to plant casuarina and eucalyptus trees along the state's entire 1,000 kilometer coastline.
I don't claim to know anything about forestation in Tamil Nadu, but on the California coast eucalyptus planting has a long history and is considered by many to be very invasive. From the National Park Service...
Blue gum eucalyptus is most invasive on sites subject to summer fog drip and rarely invasive in the Central Valley or in dry southern California locations. It produces a chemical that leaches into the soil and inhibits the growth of indigenous California plant species. Eucalyptus trees, especially the bark litter falling beneath, are extremely flammable, and are a major concern during the hot, dry California summers.
Now these ecological concerns might not apply at all to Tamil Nadu, and of course it is extremely fortunate that the plantings helped dissipate the wave energy. Just want to stress that planting trees can be complex, and that the ecological context of the species should be a major consideration.
Does anyone know if there is a consensus opinion, amongst biologists/conservationists in Tamil Nadu and other parts of the region, on what's ecologically what with those casuarina plantations?
There is anouther less known issue with eucalyptus trees they unlike most trees grow thier branches until they break off. This can cause major havok as the trees grow to be rather tall and a 600lb branch can realy squish stuff.