Systems Dynamics Simulation To Improve Timber Harvesting System Management

Abstract

Two computer simulation models were developed to address harvest system - stand assignment and wood flow variability problems in the southeast United States.

The Harvest System Assignment (HSA) model is used to evaluate the impact of a particular stand assignment on harvest system effectiveness and is designed to assist with harvest system assignment decisions. Four general harvesting systems: manual, mechanized, shovel and cut-to-length can be modeled to harvest timber, from standing trees to processed logs loaded on to trucks. Model testing showed that as terrain, tract and system characteristics changed, the effectiveness of each of the four systems varied. The most effective system can be determined for any combination of terrain, tract and system characteristics. The model output shows production potential as well as cost per unit, and identifies the causes and magnitude of inefficiency.

The Machine Allocation (MA) model is used to evaluate the potential of a given machine combination and is designed as a research tool to investigate the cause and impact of machine interactions. This model has a defined system structure and can incorporate up to five machines for each of three phases in the harvesting operation: felling, skidding and processing. Particular system configurations can be evaluated and possible improvements to machine combination determined.

The HSA model is a widely applicable tool that will be available for industry in the southeastern United States. It has utility for training of personnel and for operational use. The MA model is a detailed tool that will be used in a research capacity to advance harvesting system management.