Evaluation of a novel mobile device app for value-maximized bucking by chainsaw

Abstract

Cross-cutting of felled trees into logs (“bucking”) is a critical step in converting standing timber into end products, as it predetermines and limits number, type and value of products that can be produced from the logs. Bucking by chainsaw is currently not aided by information technology and volume and value recovery depend on the chainsaw operator’s proficiency. A recently presented novel mobile device-based application (“T4E Bucking App”) for assisting value-maximized bucking by chainsaw was evaluated during harvesting in a mature beech stand regarding taper curve estimation accuracy. Further, its bucking patterns were benchmarked against an experienced chainsaw operator’s choice and time consumption for app operation was determined. Taper curves were inadequately approximated and log mid diameters (1.0 cm, SD=2.4) and log volume (0.02 m3 under bark [UB] m3, SD=0.04) were significantly overestimated. Consequently, total observed volume (–8.7%) and value (–8.1%) were smaller than estimated. Inappropriate pricing and insufficient top diameters caused further reductions. Thus, total recovered volume (59.61 m3 UB; –8.8%) and value (€2,099.66; –8.6%) were smaller than estimated. Chainsaw operator’s totals differed marginally (58.59 m3 UB; €2,117.99). About 85% of the variation of time consumption for working with the app was explained by tree volume and number of grade sections. After accounting for time consumption, net value recovery was 5.1% lower than in the chainsaw operator’s case. The T4E Bucking App nevertheless represents a first step towards digitalization of motor-manual bucking and may soon be enhanced by more accurate taper curves derived from terrestrial laser scanning data.