ECOLOGICAL CHARACTERISTICS OF PLANT COMMUNITIES IN SWAMP FOREST OF NARATHIWAT PROVINCE

Abstract

Optimal number and size of sample plots were investigated in undisturbed swamp farest having the total area of 9,684 ha in southern Thailand. Field investigation was carried out from February to July 1987. It was found that 21 sample plots of 40x40 m in size were suitable to this study. Hence, such plot size and number were laid out for community analysis. There were 143 vegetation species in this swamp forest. The species numbers were consisted of 79 for trees, 6 for shrubs, 8 for annuals, 33 for climbers, 10 for palms, 7 for ferns, and 1 for parasite. Kaprea, an undergrowth annual crop, was found to have the highest values of relative. frequency, relative density, relative dominance, and importance value index (IVI) followed by Lam-tang Scleria sumatrensis, and Licuala spinosa. Maximum IVI among 79 forest tree species was found in Lumaitzera littored, followed by Macaranga pruinosa. Ganua motleyana. Lumaitzera racemosa. and Eugenia curtisii. These tree species played the great roles on swamp community. Normally, it was not in common for them to disappeared From the site. Vegetation having low IVI were Polygonum bydropiper. Desmos-chinensis. Ipomoea digitata, Araca sp., Mak-kun, Tard, and Fagraea auriculata. Tree species. with low IVI were Kao-maow-chang, Ficus aurantiaca, Fagraea racemosa, Persea membranacea, Lago, Podocarpus wallichianus, and Canthium congestiflorum. These species played minor roles in swamp community. It might be easy for them to be disappeared from the community.