Date of Award

Summer 8-16-2015

Level of Access

Open-Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Forest Resources

Advisor

Jeffrey G. Benjamin

Second Committee Member

Aaron Weiskittel

Third Committee Member

Mindy Crandall

Abstract

Computer simulations have been used in forestry and forest operations since around 1960. In many cases such simulations can be used to answer questions that would be time consuming and expensive to investigate in a real-life environment. This dissertation focuses on the use of computer simulation in forest operations to answer questions regarding the profitability of technological advancements, investments in precommercial thinning (PCT), and the use of different harvesting systems. To explore the benefits of decoupling a harvesting system, a new simulation method, called agent based modeling was used. Agent based modeling is primarily used in social sciences but now is increasingly used in other fields due to its flexibility in assigning behavior rules to individual object (agents). Other computer simulations in this study were based on growth & yield models and harvest time simulations.

Results clearly showed that technological advancements in a grapple skidder and stroke delimber system marginally increased profits, whereas the use of two grapple skidders proved to be most profitable in the majority of scenarios tested. Further, results showed that the same profit per unit can be achieved at the first commercial thinning, whether a stand was previously precommercially thinned or not. Thus, there is no financial gain or loss in investing in PCT at the first thinning, although there will be a faster supply of sawlogs in the future. The last simulation clearly showed that delaying a commercial thinning does not result in a change of maximum net present value (NPV), however, it does change the time in which this NPV can be achieved. The simulation further showed that a cut-to-length harvesting system is the most profitable one in the final harvest of softwood stands in northern Maine.

Overall, these simulations have provided data that in most cases would otherwise not have been possible to collect for years to come. In the future each individual study can be expanded to refine the questions asked or to include an increasing variety of harvesting equipment.

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