Mohammad Reza Ghaffariyan

Production Equations for Tower Yarders in Austria

Abstract Cable yarding has been used for many years in mountainous forests in central European countries. Tower yarders are common cable yarding systems in Austria. The goal of this study was to develop a general time prediction model for two kinds of tower yarders used in Austria. The multiple regression method was applied. The average production rate was 9.30 m3/PSH0 with a cost of US

A model to predict productivity of different chipping operations

25.48/m3. The results also showed that the production rate for downhill yarding was less than uphill yarding using the Syncrofalke tower yarder. The developed time production models can help forest engineers estimate production of tower yarders in similar logging operations.

Integrated harvesting for conventional log and energy wood assortments: a case study in a pine plantation in Western Australia

The chipping operation is an important component of harvesting systems producing biomass and pulp chips. This paper aimed to develop a valid model to predict the productivity of chipping as part of these operations. Over a number of years more than 200 different time studies were conducted on chipping operations in Italy and Australia. Multiple regressions and backward stepwise data analysis methods were applied to develop a productivity prediction equation, considering the following variables: machine power (kW), piece size (m3), crew size, harvesting method, species, tree part, wood condition, wood lay-out, chipping type, propulsion, feeding method, point of chipping, season, location of chip discharge, country (Italy or Australia) and type of operation (biomass chip operation or pulp chip operation). The final productivity model included machine power, average piece size, location of chip discharge and type of operation as significant variables. The internal validation test was conducted using five witness samples from Italy and Australia, which confirmed the validity at α=0.05. Additional international case studies from North America, South America, and central and northern Europe were used to test the accuracy of the model, in which 15 studies confirmed the models validity and two failed to pass the test.

Quantitative and qualitative assessment of timber harvesting residues: a case study of a balsa plantation in Papua New Guinea

Biomass or energy wood harvesting can be integrated with conventional log harvesting (saw log or pulpwood production) to allow more cost-effective energy wood supply. The efficiency of an integrated energy wood harvesting system was evaluated and compared with conventional log harvesting in a 32-year-old Pinus radiata plantation (radiata pine) located in south-west Western Australia. The harvesting system consisted of a harvester and a forwarder. The study included two treatments: a conventional log-harvesting operation where merchantable sawlogs and pulp logs were produced at the stump by the harvester and extracted by the forwarder; and an integrated energy wood operation where the harvester produced sawlogs, pulp logs and energy wood at the stump that were extracted by the forwarder. In the integrated energy wood harvesting plot, 37 m3 ha−1 of energy wood was extracted in addition to the sawlog and pulp log volumes. Extracting the additional energy wood reduced the productivity of the forwarder and increased the cost of extraction (AU

Analysing the effect of five operational factors on forest residue supply chain costs: a case study in Western Australia.

2.7 m−3) compared with the control plot (AU

Optimising transport efficiency and costs in Australian wood chipping operations

2.2 m−3). Harvesting system cost was not significantly impacted, with a cost of AU

Optimal road spacing of cable yarding using a tower yarder in Southern Austria

3.18 m−3 in the control plot and AU

An international review of the most productive and cost effective forest biomass recovery technologies and supply chains

3.23 m−3 in the integrated energy wood harvesting plot. Diameter at breast height (DBH) was a significant factor influencing the working time of the harvester, whereas load volume, extraction distance and extraction type (sawlog, pulp logs, and pulp log/energy wood) significantly impacted forwarding time. Increasing DBH resulted in longer working cycles for the harvester. Heavier loads and longer forwarding distances increased forwarding cycle time, while extracting sawlogs was least expensive and energy wood extraction was the most expensive. The marginal cost of the energy wood was approximately AU

Road network optimization using heuristic and linear programming.

10.2 m−3 (AU

Evaluating productivity, cost, chip quality and biomass recovery for a mobile chipper in Australian roadside chipping operations

7.0 extraction and AU