Multi-Stem Mechanized Harvesting Operation Analysis – Application of Arena 9 Discrete-event Simulation Software in Zululand, South Africa
Authors
Glynn A. Hogg
Department of Forest and Wood Science, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
Reino E. Pulkki
Faculty of Natural Resources Management, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, Canada, P7B 5E1 and Department of Forest and Wood Science, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
Pierre A. Ackerman
Department of Forest and Wood Science, Faculty of AgriSciences, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
Abstract
Time studies were carried out on a stump-to-mill multi-stem Eucalyptus harvesting and transport operation in Zululand, South Africa in 2007. A simulation model (System 1) of this system was subsequently built using a commercial simulation software package (Arena 9) and data from the time studies incorporated into the model. Following this, two hypothetical stump-to-mill multi-stem models (Systems 2 and 3) were built using Arena 9 and parameterized input data. All models were found to adequately represent reality. Simulated harvesting system balance was improved through normalization of machine utilization in Systems 2 and 3. Production improvements were predicted with simulated timber production per month increasing by 31.1% and 30.8%, from System 1 with three trucks, to System 2 with four trucks, and System 3 with four trucks, respectively. Cost reduction was predicted, with the cost per unit of timber decreasing by 12.5% and 4.1%, from System 1 with three trucks, to System 2 with four trucks and System 3 with four trucks, respectively. Beneficial operational techniques were also confirmed using the simulation models. In the studied conditions delimbing and debarking of full trees into tree lengths at roadside with delimber-debarkers before cross-cutting and loading with a slasher was predicted to be $0.65/m3 cheaper than delimbing, de-barking, and cross-cutting full trees into pulpwood with processors at the landing and then loading with a loader. Usability of Arena 9 in modeling forest harvesting operations was concluded as acceptable, but required detailed background logic inclusion.
