Productivity of a cut-to-length harvester family - an analysis based on operation data

In forest operations, productivity analyses have mainly been based on time studies. With the increasing appli- cation of computer technology, operation data could be captured automatically or at least semi-automatically. Under central European conditions, operation data are usually recorded on the cutting-unit level. The aim of this study was to develop a productivity model for a whole family of cut-to-length harvesters. More than 2200 data records were available, covering 12 different harvester types. The statistical analysis was based on a linear model with covariates and factors. Here, stem volume explained about 63% of the total variability, while machine type contributed about 11%. The two major findings from this study were that: (1) it is possible to quantify productivity differences among harvester makes, and (2) the influence of tech- nological advances can be estimated. However, data quality was inconsistent because of differences both in recording pro- ductive-system time due to registration methods (manual, electronic, mechanical), as well as in stem volume calculations (e.g., harvester computer, volume calculation at the mill, volume designated according to grading rules). The next steps for improvement will be to standardize data capture and develop productivity databases on a regional or even an industry level.