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Browsing by Subject "paljaan maan arvo"

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  • Kuusikon harvennusmallien ja kiertoaikojen taloudellinen tarkastelu 
    Laiho, Toni (2014)
    The aim of this study is to examine the profitability of cultivation and stand rotations of Norway spruce in Finland. This information is needed by the forest owners when making decisions on forest cultivation. The results were compared to previous studies and to silviculture recommendations published by the Forestry Development Centre TAPIO’s in 2006. Forest management chains used in this study were simulated with the Forest Research Institute’s Motti program. Six different management chains in two different forest types, Oxalis-Myrtillus (OMT) and Myrtillus (MT), were simulated in the thermal area of 1300 with planting density of 1300, 1700 and 2100 per hectare. Either one, two, three or four thinnings were done for each of the planting density variations. Based on the results from these cultivations, the spruce cycle was analysed by comparing the value of the growth to alternative rates of return. Profitability calculations were based on the Motti programme and timber stumpage prices were obtained from the Metinfo service. The results showed that the optimal rotation periods were in line with previous studies. The rotation periods settled between 60–90 years depending on the rate of return that was required. However, the results were not identical to the theoretical optimum models. The Motti program forest management recommendations, are in line with the previous studies when requiring a four percent return. Sensitivity analysis of prices and costs were calculated for the rotation and based on the results, even by varying the price and cost by one third, this had very little effect on the optimal rotation time. The most important factor for the rotation period is the function of the tree's growth, which of course, is affected by the forest management measures.
  • Optimal harvesting of Tectona grandis plantation stands in Costa Rica 
    Malmström, Miika (2013)
    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.

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