EVALUATION OF BIOME-BGC MODEL FOR ESTIMATING NPP AND LAI OF TEAK PLANTATION OF THAILAND USING SPOT-DATA AS REFERENCE

摘要

In this study, BIOME-BGC was used to estimate the NPP and LAI of Teak plantation during 2004-2007 at Mae Moh site, Thailand. The model general ecophysiological parameterization defined by White et al (2000) was used, except the dates for vegetation onset and offset which was particularly specified for this site. Several climate parameters were generated by MT-CLIM based on meteorological data observed at the field. The outputs of BIOME-BGC are validated by SPOT s10 data. The LAI from SPOT and LAI observed from field has a good correlation (R~2 = 0. 80) and small RMSE of 0.86. Then LAI from SPOT is used to validate the simulated LAI from the model. Similarly, LAI observed from SPOT and LAI simulated from the model presented an acceptable correlation of (R~2=0.67). The RMSE result of the observed LAI from SPOT and simulated LAI from model showed a small enough at 1.05. This is because of the facts that the pixel that SPOT detected contains not only teak but also many varieties of species at below canopy and the ecophysiological constants of BIOM-BGC is not specified for teak. The estimated NPP from BIOM-BGC in these four years of evaluation was 776.1, 740.4, 605.6 and 687.4 gC/m~2/y respectively. The results from sensitive analysis of simulated NPP to meteorological input parameters demonstrated that NPP at the site is sensitive to precipitation and VPD. The method is feasible to estimated NPP of teak by applying BIOME-BGC in tropical area.