Browsing by Subject "Tectona grandis"

This thesis studies the economically optimal timing of thinnings and final harvest on Costa Rican Tectona grandis plantations. Consequently this thesis studies the profitability of the plantations and makes a comparison to previous studies. Optimization is based on programming with AMPL with Knitro optimizing software. The objective function used is the Faustmann formula. Different rates of interest are used. The ecological functions used for the modeling were obtained from previous studies by Pérez and Kanninen (2005a). The economic data such as planting and thinning costs and log prices were obtained from a T. grandis plantation specialist. The results of the study show that the optimal harvesting regime in T. grandis plantations differs from what is suggested in literature. The main findings are that the optimal rotation length is shorter and both timing and intensity of the thinnings vary depending on the rate of interest used. In addition the maximized bare land values under optimal management regimes are notably higher than bare land values under previously suggested management regimes. The management regime is highly sensitive to the rate of interest used. The management regime is less sensitive to the changes in price than expected. This thesis suggests that the initial density of 816 ha-1 trees results into higher bare land values than 1111 ha-1 trees . However, the difference is minor and possible increase in silvicultural costs is not considered. In addition a simple test is carried out to see the possible effects on heartwood proportion growth to the optimal management regime. The shortcomings and possibilities to improve the model are discussed. It is noted that the price data for T. grandis is not coherent, and that the ecological model could be improved in order to increase its accuracy.