Spelling suggestions: "subject:"logging -- amathematical models"" "subject:"logging -- dmathematical models""
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Improved forest harvest planning : integration of transportation analysis with a management unit cut scheduling modelYamada, Michael M. January 1980 (has links)
Forest harvest planning involves determining, in time and place, the flow of timber to be generated from the forest resource. Existing planning models have addressed the temporal aspects of timber supply. However, the spatial aspects of timber supply planning, particularly at the management unit level, have principally been ignored.
This study presents an analytical framework for examining the transportation system of a management unit, its interrelationship with the timber base, and the impacts on strategic harvest planning. The transportation system is evaluated through network analysis techniques. Routing strategies from the stand to the mill are examined. The costs of primary access development and log transport are integrated with the forest inventory, providing a more complete assessment of timber value. Homogeneous stand aggregations and associated yield projections, pertinent to management unit planning, are formed using factor and cluster analysis. Dynamic programming allows optimal allocations of the stand groupings across stratifications which recognize transport and accessibility costs. The resulting timber classes are coupled with management prescriptions and evaluated through a cut scheduling model. Report generation capabilities then allow interpretation of the harvest scheduling results in terms of not only the timber classes, but in the spatial context of the individual stands. The methodology is applied to a British Columbia Public Sustained Yield Unit. The usefulness of the system is demonstrated through analyses which:
1) identify road development and transport costs,
2) evaluate alternative wood flow patterns,
3) identify the volume flow potential of the unit,
4) identify the dollar flow potential of the unit, and 5) illustrate the contribution of integrating the transportation system in the scheduling of harvests. / Forestry, Faculty of / Graduate
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A Markov process methodology for modeling machine interactions in timber harvesting systemsHassler, Curt C. January 1985 (has links)
Recent advancements in timber harvesting systems analysis have been almost exclusively simulation based. A similar degree of effort in developing analytic models has been conspicuously absent.
That part of timber harvesting analysis where simulation plays its most vital role is the study of machine interactions. The importance of machine interactions lies in determining the proportions of delay, idle and productive time for the interacting machines. This in turn, is important for balancing productivity so that no single component of the interaction is accumulating excessive amounts of delay or idle time.
The objective of this study was to determine the feasibility of applying Markov process theory to the analysis of timber harvesting systems and components. Through modeling the interaction between a fixed location slasher and a grapple skidder, it is shown how a Markov model can be used to obtain proportions of delay, idle and productive time. Unlike the statistical solutions derived from simulation models, the Markov model improves upon this by providing an analytic solution. The Markov model also avoids the problems of correlated output data from simulations by explicitly recognizing that any possible future state is dependent only on the current state of the system and is conditionally independent of the past history of the system.
The methodology for building a Markov model requires dealing with only two probability distributions, the Erlang and mixed Erlang, for modeling time based activities (such as cycle times) of the interacting machines. These probability distributions in turn, provide the necessary data for developing a system of algebraic equations for solving the Markov process model.
While this is the first step in applying stochastic process theory to timber harvesting analysis, the results of this study indicate that the technique has considerable potential for application in timber harvesting system modeling. / Ph. D.
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Stumpage price expectations: an empirical analysis of nonindustrial private landowners in the Mid-Atlantic statesLawrence, Gerald D. January 1985 (has links)
Numerous empirical studies outside of forestry have analyzed the role of price expectations in different decision processes. Empirical studies using price expectations in forestry research is a relatively new field of endeavor. Past studies have typically ignored or given cursory treatment to the role of price expectations.
This study provides a review of studies in forestry that have attempted to incorporate price expectations into model formulations. Models are then developed to explain the short-run harvest, and long-run regeneration expenditure decisions by the non-industrial private forest owner, incorporating different distributed lag formulations to account for price expectations.
The estimated models for the short-run harvest decision, using cross sectional non-aggregated data, indicates that price expectations play a significant role in this decision process. Therefore, price expectations should be incorporated in some form, (i.e. different forms of distributed lags), to properly specify models. Estimated models for the long-run regeneration expenditure decision indicates a weak link between economic variables and the regeneration decision.
For both types of models, estimated coefficients for personal characteristics of landowners are in general considered insignificant, indicating the lack of influence that personal characteristics have on these decision processes / Master of Science
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