Researchers examined this question using a case study from western Oregon.
Adoption of tethered-assist harvester technology on steep terrain by the forest industry has decreased workplace accidents. However, there are portions of harvest units that remain inaccessible to mechanized falling, therefore requiring manual falling as well. This study characterized the differences in terrain and forest conditions between manual and machine felled areas within the same harvest units.
The researchers wished to determine whether manual fallers will work more time in challenging terrain on harvest units using both mechanized and manual falling when compared to harvest units using manual falling only. This was tested using field data from three new harvest units, six previously harvested units, timber faller surveys, and harvest managers’ interviews. For both field datasets, only slope was the factor predicting falling method. Further, both managers and fallers confirmed steep slope as one of the main reasons for requiring manual falling in addition to rocky bluffs, unstable terrain, and lack of access.
This study indicates that when harvest units on steep terrain are felled with mixed falling methods, timber fallers likely work on steeper slopes than the machine, and spend a larger proportion of work hours on steeper ground than the average slope of a harvest unit. The consequence is that forest managers needs to pay particular attention to the increased risks posed by constantly working on difficult terrain. Source