Key factors influencing productivity of whole-tree ground-based felling equipment commonly used in the pacific northwest

Around the globe, various types of forest machinery are employed to conduct fully mechanized ground-based timber harvesting. In the Pacific Northwest, the whole-tree harvesting method remains dominant. While machine-integrated sensors provide accurate productivity information in the cut-to-length harvesting method, productivity is more complicated to determine in whole-tree harvesting. This literature review compiles and analyses the existing evidence on productivity studies of feller–bunchers and feller–directors in a systematic manner and identifies the factors influencing machine productivity. The study indicates that most of the previous research was conducted in North America, particularly in Canada. It was also found that a considerable portion of the literature lacked statistical analysis. Piece size, slope, and silvicultural treatment were the most commonly studied productivity-influencing factors among the results. Although there is already a general understanding of the most important factors influencing the productivity of feller–bunchers and feller–directors, there is still a lack of accurate measurement and isolation of individual factors to facilitate accurate productivity prediction. Further research is needed for the development of systems that use integrated sensors capable of estimating machine productivity. Updated productivity models will optimize harvesting operations, identify bottlenecks, and allow for the development of best practices.