Estimation of Forest Plantation Productivity Using a Physiologically Based Model Driven with Meteorological Data and Satellite-derived Estimates of Canopy Photosynthetic Capacity

Abstract

Within the framework of Kyoto protocol, carbon sink concept is a major topic for the global climate change. There is an urgent need to collect some necessary data on the forest plantations. Therefore, there is a clear need to develop methods for estimating the biomass at diverse sites simply with non- destructive methods. Modeling is one of effective approaches and Process Based Models (PBMs) can provide a better understanding of stand growth and dynamics. A one simplified model of PBMs is 3PG model and modified one is 3PGS model; Physiological Principles Predicting Growth with Satellite data (1). The model enables to use parameters derived from satellite data such as Fraction of absorbed Photosynthetically Active Radiation (FPAR) as well as meteorological data. The objective of this study is to compare between 3PG model and 3PGS model by estimating above ground biomass (Wabv). Landsat Enhanced Thematic Mapper-Plus (ETM+) data were used for the model implementation. The estimated parameters were validated with the ground-measured values. Field measurements were conducted in Eucalyptus camaldulensis and Acacia mangium plantation. The 3PGS model outputs showed that there was very good relationship between measured (ground-based measurements) and simulated (modeled) values. Root mean square errors (RMSE) of 3PGS model results were less than the RSME of 3PG model results in Eucalyptus plot. The result applied for Acacia mangium showed it had higher RMSE between measured and simulated values than the result applied for Eucalyptus camaldulensis. The results indicate that the 3PGS model can provide reasonable estimates of Wabv.