2006 Volume 48 Issue 1 Pages 43-56
We surveyed the impact of Tsunami, which slaughtered the coastal zone surrounding Andaman Ocean in December 26th, 2004, on the coastal vegetation at west coast (Krabi, Phuket, Pang-nga, and Ranong) of Malay Peninsula in southern Thailand in middle of March, 2005. Casuarina forests including some plantation aged ca. 30 years old distributed on the sandy beach and natural mangroves developed on riverine and basin peaty habitat were the major forest types in this area. Some Melaleuca forests as well as Coconuts plantations were also observed at interior regions. Serious damages of buildings and/or on human were observed in the beach resorts and fishery villages facing to the Andaman Sea at where the elevation is low. We recognized that mangroves, especially Rhizophora forests could mitigate Tsunami damage by trapping many flown wreckages within the 10m from forest edge, which saved many lives at interior. It was thought that highly developed above ground stilt root system of mangrove contributed to the trapping effects. Remarkable trap effect was not observed in Melaleuca forests and Coconuts plantations with low tree density. Large Casuarina trees at water front were found to be uprooted by erosion and small Casuarina trees were all mown down by direct impact. Unusual defoliation of trees was also observed in many places. Herbs and shrubs grown under the Casuarina stands were also mown down and buried by sand from shallow water of west coast. This sand deposit may present the smooth respiration of mangrove roots and affects on their survival seriously in near future. At the beach forests e. g. Melaleuca forest covered by sea water began to show the chlorosis of leaves and unusual defoliation considered to be the damage by saline condition were observed. We predict that the Tsunami damage of coastal forest appears not only as the direct impact but also appears as the gradual, severe and long lasted deterioration of forest health.
