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UBC Theses and Dissertations

Microstand : a computerized learning tool for evaluating forest stands Masse, Sylvain


The main objective of this thesis was to develop a computerized stand management analysis program based on the Lotus 1-2-3™microcomputer software that would be suitable for use as a stumpage appraisal learning tool for University of British Columbia (UBC) undergraduate forestry economics courses. A secondary objective was to assess the appropriateness of Lotus 1-2-3™ for developing interactive and user-friendly stand management analysis programs. MICROSTAND is a stand level program composed of stumpage appraisal submodels fed by a growth and yield simulator and linked to some financial analysis devices. The general conditions being simulated are Crown timber of British Columbia's coastal area; pure stands composed of one of four important commercial species; three basic scenarios corresponding to thinning only, final harvest only, and thinning followed by final harvest; a simulation period ranging from one to 100 years; and a 1985 base year for costs and revenues. For each scheduled harvest, the growth and yield simulator generates output yield variables which are then used by the timber-log conversion simulator to transform the timber harvested into logs. The log grading simulator then estimates a grade distribution, and the revenue simulator then applies log prices to the grade distribution. The costs associated with each harvest (direct costs per delivery phase, return on capital and a special risk allowance) are then estimated by the delivery cost simulator. Finally, user-specified average real rate of change in revenues, average real rate of change in costs, and real discount rate are used by the financial analysis simulator to produce the following data: cash flow of real revenues and costs over the simulation period, residual timber value at each harvest, and net present value and benefit-cost ratio for the stand management scenario. The reactions to thinning, the distribution of log volume among grades, and the return on capital are generated by unsophisticated simulation procedures that were not tested with empirical data nor validated models. The program-user interactions are controlled through menu options, growth and yield graphs can be produced, and information notes can be displayed. Sensitivity analysis on appraisal determinants can be conducted by returning to previous input phases. MICROSTAND is a suitable stumpage appraisal learning tool for UBC undergraduate forestry economics courses due to seven characteristics: simulation of representative British Columbia coastal conditions, user-friendly operation, inclusion of critical appraisal determinants, generation of detailed outputs, flexibility, and recognition of both uncertainty and relevant economic concepts. The inclusion of unsophisticated and nonvalidated simulation procedures does not prevent MICROSTAND from revealing the nature and the interrelations of the main appraisal parameters, with the sole exception of tree size variations in a stand and the consequent effects on log revenues. Recognition of tree size variations could be obtained with a valuation procedure based on empirical data and regression techniques. A limitation of MICROSTAND is its relatively slow processing speed which is mainly due to two characteristics of Lotus 1-2-3™: the recalculation of all the cells in a worksheet when a value or a formula in one of the cells changes, and the necessity to transpose DO LOOPS through iterative procedures. Lotus 1-2-3™ proved to be an appropriate medium for developing interactive and user-friendly stand management analysis programs, despite coding complications and possible slow processing speed. The programming approach developed for MICROSTAND appears to be a flexible framework suitable for a variety of interactive programs related to forest management and other fields. Simulator simplification by regression techniques is recommended in order to improve program performance. It is also suggested that the development of multistage programs such as MICROSTAND could benefit from a multidisciplinary team approach.

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