¹Faculty of Forestry, Kasetsart University Bangkok, THAILAND

fforsna@ku.ac.th

　

²Faculty of Engineering, Seikei University Tokyo, JAPAN

katos@mserv.cc.seikei.ac.jp

　

Mangrove forests are endowed with rich and divers living resources in various countries particularly Thailand of the Tropical coastal areas. These areas have long been of great importance in the subsistence of a large percentage of human population. More recently, mangrove have become of great economic significance both in terms of their direct resource utilization in forestry and fisheries production and in view of their potential in protecting coastlines and maintaining estuarine ecological balance.

　

Mangrove forests in Thailand have been destroyed for many years by several human activities. The country now recognizes the need for sustainable management and conservation of mangrove resources. Various tools used in managing mangroves are setting up mangrove land-use as conservation and development areas, managing for the integration of forestry and fishery production. Education and public participation are crucial factors in mangrove rehabilitation and conservation of the country.

　

　

¹Prince of Songkla University, THAILAND

²Kasetsart University, THAILAND

³Seikei University, JAPAN

^4,5Regional forestry office, NST, THAILAND

　

Rehabilitation of mangrove forest under the Green Carpet Project supported by KEIDANREN Conservation Fund (KNCF) and Japan Fund for Environmental Conservation (JEC) has been carried out in Nakhon Si Thammarat Province, Southern Thailand. The aim of this project is to develop coastal resource and environment by planting mangrove along the coastline mainly in abandoned shrimp ponds and some new mudflats. The total planting areas as planned are about 1,000 ha within 5 years. For this study, growth and survival rates of mangrove species planted in abandoned shrimp ponds in December 1997 were monitored to compare with those in the following years. Soil samples for each planting site since 1997 were also analyzed in order to assess the changes of soil properties after planting mangroves. The results for four mangrove species measured in the third year (September, 2000) showed that Rhizophora mucronata and Rhizophora apiculata grew well under this condition (176.6 cm-height; 141 leaves; 3292 g-biomass for R, mucronata and 120.6 cm-height; 900 leaves; 3,000 g-biomass for R. apiculata) with high survival rates (90.0% and 73.3% respectively). Ceriops tagal also grew well (59.1 cm-height; 162 leaves; 337.7 g-biomass) but the survival rates decreased in the coming year (63.3%). Among four species, Bruguiera cylindrica was the lowest for growth rates (46.0 cm-height; 117 leaves; 156.7 g-biomass) with very low survival rates (26.7%). In addition, growth of R. mucronata planted in March 1999 or at the second year of the project showed very good performance (95.8 cm-height; 57 leaves; 357.9 g-biomass) with high survival rates (exceeding 90%). Interestingly, eight-month old R. mucronata, which was planted in the third year of the project (January 2000) showed 95% survival rate and good growth performance (97 cm-height; 25 leaves; 279 g-biomass) indicating the suitability of this species to the site. As for soil monitoring, soil properties were determined across a range of mangrove ages for three years. In general, significant increases in organic matter and total nitrogen in soil were detected across planting sites as well as mangrove ages. The organic mater, for example in the ponds where mangrove were grown in 1997 was found 69.4% increase in the third year indicating the importance of biomass allocation of mangrove to the planting site. Similarly, an increase of 166% total nitrogen was recorded form year 1998 (0.09%) to year 2000 (0.24%). The CEC (26.0 meg / 100 g) and pH (7.8-8.2) values were found to be quite consistent to year 2000. Other plant nutrients such as phosphorus and sulphur demonstrated inconsistent values across mangrove ages and planting sites, but sharp declines were observed for potassium, calcium, magnesium and sodium contents in the third year. Key words: mangrove rehabilitation, abandoned shrimp ponds, Rhizophora, mangrove growth, mangrove soil

　

　

¹Abiko Research Laboratory CRIEPI Abiko, Chiba, JAPAN

tateda@criepi.denken.or.jp

　

²Japan Ocean Industries Association Minatoku, Tokyo, JAPAN

　

The overall objective of the research project is to control global warming by sequestering carbon dioxide from the atmosphere by mitigation of Asian mangrove coastal ecosystems. In this respect, we studied to validate the carbon storage effect of tropical mangrove coastal ecosystem by conducting field study in the mangrove ecosystem of Ishigaki Island Japan and Trat province, Thailand.

　

For wide area estimation of mangrove total carbon storage and GPP (Gross primary production) by satellite data, we collected data of Rhizophora tree samples including root system and Leaf Area Index (LAI). Direct photosynthesis and respiration measurements of every parts of mangrove are also analyzed to estimate accurate CO₂ sequestration and respiration by mangrove tree community.

　

The CO₂ sequestration by mangrove coastal water are measured by under water respiration meter and dissolved oxygen analysis in mangrove coastal waters. Organic carbon, nutrients, microbial concentrations in water were proved to be critical in gasses emissions by underwater organic matter decomposition, especially CO₂ emission from organic matter degradation in sediment bio-turbation.

　

Ishigaki Island and Trat area study indicated that CO₂ emission not only from underwater sediment but also air-exposed sediment surface and bio-turbated deep sediment. Organic matter accumulation by sedimentation was estimated, indicating that small fine refractory organic matter is main accumulator of fixed CO₂. N₂O was emitted from mud flat in mangrove forest. Chemical and nutrient conditions of mangrove sediment indicated significant correlation between pH, Redox potential, potassium, hardness and mangrove tree height.

　

　

Department of Marine Science Chulalongkorn University Bangkok, THAILAND

　

It had long been recognized that protection of any area by government authority alone might not always been successful. Coastal Resources have been deteriorating continuously in spite of the effort from the government to set up more "Marine National Parks" and "Reserved areas". Some Marine Parks are well managed with adequate support of manpower as well as budget, so natural environment have well been protected while many others are still lacking support enough to maintain the parks properly. Mangrove reserves seems not as strong as marine parks, many areas had been clear-cut, invaded for varieties of reasons including human settlements, industries, etc., and most destructive of had been the conversion of mangrove into shrimp farms. National policy had to be changed and as of now wherever mangroves are still existed, those areas would be counted as mangrove-reserved area and not to be used. Seagrass beds are even more exposed to destruction factors such as; from trawlers mollusks (Papia) dredges, or even coastal construction coral reefs are degrading by both natural factors, such as bleaching, as well as by touristic activities. Local people in many areas in Thailand, through the assistant of NGOs are working with local authorities in protecting the natural resources in their areas. Many successful cases are now evidenced. Through the process, many difficulties had been encountered. In many cases, the problems had turned to be so serious that the conflict ended with the lost of life of some people. Through communities-strengthened process, at present, many areas are well protected and the local people are enjoying in having the richness of resources coming back for their use.