Katavut Pachana

Estimation of biomass and carbon stock in Para rubber plantations using object-based classification from Thaichote satellite data in Eastern Thailand

Abstract. This paper deals with the efficiency of measurements of carbon stock by remote sensing techniques on Para rubber plantations in Thailand. These plantations could play an important role in carbon budget and thus are part of the Clean Development Mechanism of the Kyoto Protocol. Current methods of carbon stock estimations use middle resolution images and produce results with a large uncertainty. We use very high resolution images from the Thaichote satellite, associated with field measurements to estimate the carbon stock and its evolution in the Mae num Prasae watershed, Eastern Thailand. Using object-based classifications, the plantations have been mapped and their age has been estimated from a parametric model derived from both spectral and textural information and field data. The total biomass and carbon stocked are 2.23 and 0.99 Megaton with an uncertainty of 11%. One hundred and twenty one tons of carbon are sequestered annually in the Para rubber plantations of the studied area.

137Cs Adsorption and Desorption on Marine Sediments from the Upper Gulf of Thailand

Sediments play an important role on fate in the diffusion of radionuclide in aquatic systems. In this study, the investigation of the adsorption/desorption kinetic of 137Cs in two different characteristic of marine sediment samples (organic matter, CEC, and clay content). Batch experiment was carried out from the Upper of Gulf Thailand. The results have shown that there is a significant percentage of 137Cs is adsorbed in both marine sediments during the first 48 hour that increased adsorption percentage to 82 and 86% and after that become to stable. On the other hand, the desorption of 137Cs was found both marine sediment were desorbed less than 10 % and become to stable desorption after 24 hours. Among different marine sediments (St.1 and St.21), the Kd value (distribution coefficients) of 137Cs was different which Kd of sediment from station 1 more than station 21(342.9 and 247.5 L/kg respectively). Differences in the characteristics of marine sediments affect to different the Kd value.