A comparison of two methods of data collection for modelling productivity of harvesters : manual time study and follow-up study using on-board-computer stem records
Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Marin Dracea National Research-Development Institute in Forestry
Abstract
Abstract. Productivity of a mechanized P. patula cut-to-length harvesting
operation was estimated and modelled using two methods of data collection:
manual time study and follow-up study using StanForD stem files. The objective
of the study was to compare the productivity models derived using
these two methods to test for equivalence. Manual time studies were completed
on four different machines and their operators. Two Ponsse Bear harvesters
fitted with H8 heads, and two Ponsse Beaver harvesters, fitted with
H6 heads, were included. All machines were equipped with Ponsse Opti2
information system. All four operators had approximately 1 year of experience
working with their respective machines. The four machines worked in
separate four-tree-wide harvesting corridors, and they each harvested 200
trees. Individual tree diameter at breast height (DBH), and height measurements
were made manually. Subsequently, data on the trees in each study
were extracted from the StanForD stem reports from each of the harvesters.
Cycle times in the stem reports were determined based on the difference
between consecutive harvest timestamps. The two methods were compared
in terms of their abilities to estimate equivalent measures for tree DBH, volume,
and productivity. In all four cases, significant differences were found
between the DBH and volume measures derived using the two methods.
Subsequently, the volume measures from the manual methods were used as
the basis for productivity calculations. Results of the productivity comparisons
found no significant differences between the models developed from
the two methods. These results suggest that equivalent productivity models
can be developed in terms of time using either method, however volume
discrepancies indicate a need to reconcile bark and volume functions with
the high variability experienced in the country.
Description
CITATION: Brewer, J., et al. 2018. A comparison of two methods of data collection for modelling productivity of harvesters : manual time study and follow-up study using on-board-computer stem records. Annals of Forest Research, 61(1):109-124, doi:10.15287/afr.2018.962.
The original publication is available at http://www.afrjournal.org
The original publication is available at http://www.afrjournal.org
Keywords
CTL harvesting, Harvesting, Farm mechanization, Wood products, Harvesting machinery
Citation
Brewer, J., et al. 2018. A comparison of two methods of data collection for modelling productivity of harvesters : manual time study and follow-up study using on-board-computer stem records. Annals of Forest Research, 61(1):109-124, doi:10.15287/afr.2018.962