Machine harvester productivity: A Queensland case study

This research studied the harvesting and processing productivity of cut-to-length and whole-tree harvesting operations in the southern pine plantations of Queensland, Australia. Elemental time and motion studies were completed for the harvesting of each system, a cut-to-length harvester-processer and a whole-tree feller-buncher and processor were observed with productivities of 75, 382, and 171 m³/PMH₀, respectively.

From this study, characteristic productivity models were generated for these systems with logarithmic and linear curves most closely representing the observed conditions. It was found that the observed values for the harvester-processor were 15% greater than the Australian Logging Productivity and Cost Appraisal [ALPACA] regional harvesting model; wheras, the whole-tree-processing productivity observed exceeded the model’s estimation by more than twice and the operating conditions of the feller-buncher were outside the bounds of the model.

Results indicated that the ALPACA model is likely not a good characterisation of Queensland operation conditions and needs to be updated to include more-refined estimates of whole-tree operations and regional merchandising conditions.

Furthermore, this work highlights the need for additional whole-of-systems productivity and economic reviews when determining the optimal harvesting system for cost reduction and value recovery (i.e. the maximising of the economic outcomes from a harvest within the context of associated markets) among competing systems in the region.

Authors: Michael Berry, Virginia Polytechnic Institute and State University Blacksburg, M Strandsgard, University of the Sunshine Coast, M Ghaffariyan, University of the Sunshine Coast, and R Mitchell, University of the Sunshine Coast.