Evaluating efficiency, chip quality and harvesting residues of a chipping operation with flail and chipper in Western Australia

Roadside chipping is a common harvesting system in Australian plantations, which utilizes a mobile chipper stationed at the field edge to produce high-quality pulp chips for export. The studied harvesting system included a feller-buncher, two grapple skidders, a flail-debarker and a disc chipper. The study goals were to determine machine productivity, operation costs, fuel consumption, chip quality and measure the amount of slash left in the field after harvesting. The average productivity for feller buncher and skidder were about 97.26 GMt/PMH0 and 60.22 GMt/PMH0, respectively. The productivity of flail and chipper averaged at 57.80 GMt/PMH0 and 58.18 GMt/PMH0 in this case study. The transportation productivity averaged about 57.34 GMt/PMH0. Time studies and regression analysis were used to model machine productivity. Tree size had significant impact on the feller-buncher productivity, while skidding distance was a significant variable affecting skidding productivity. Operation costs were evaluated using the ALPACA (Australian logging productivity and cost appraisal) model. This paper offers valuable information about the impact of different factors on feller-buncher and skidder productivity. Application of two skidders resulted in high total operating cost. Extracting whole trees to roadside yielded a very small amount of remaining slash distributed on the site.