Speaker
Description
Skogforsk has carried out reoccurring tests of harvesters with a focus on value recovery (including e.g. damages, measuring accuracy, optimization efficiency) and StanForD implementations since the mid 1990’s. A new test with seven different final felling harvesters was carried out in the autumn of 2025 in one single location north of Uppsala. The test was carried out in a Norway spruce stand with an average stem size around 0.9 m3sub where each machine harvested at least 220 stems and 34 of these stems were manually control measured. The test also included, for the first time, an evaluation of the precision of stem coordinates from harvesters equipped with high precision GNSS systems.
All active manufacturing members in the StanForD working group were invited to participate. The following harvesters participated:
Base machine Harvester head Controller
Komatsu 951 C144 MY23 MaxiXT
Rottne H21 EGS706 Dasa Forester H70
Ponsse Scorpio Giant New Ponsse H7 Opti 5G
EcoLog 590G Ec661 Lf Dasa Forester H70
Logset 12H Logset TH80 TOC-MD
JohnDeere 1470H H425 Timbermatic H
Tigercat 1165 Log Max 5000V Log Mate 510
It is possible to analyze the historical development of several key figures as this type of test has now been carried out five times with the same basic methodology. The presentation will thus include comparisons between the harvesters in the present test as well as general comparisons over time.
The presentation will include results on length, diameter and volume accuracy for the different harvesters where manual control measurements are used in order to compare with the values generated by the harvester. Results on the performance of the bucking optimization will also be presented including the effect of the measuring errors. All harvesters today have the possibility to use two different optimization methods and results for both methods are thus included in the study. The overall trend is that the measuring accuracy has improved since the previous test (e.g. standard deviation for diameter measurements has decreased from 2,3 mm to 1,4 mm since the test 2006) and that the bucking optimization algorithms are performing as expected (≈99% of theoretical maximum).
The test also included a thorough analysis of the implementation of the StanForD standard including what data is available from each control system and what StanForD version that is supported. Three of the harvesters had implemented the latest StanForD version (4.1) which enhance the reported production data, especially when it comes to positioning information such as the log positions. Another important aspect was to test and verify that the flexibility in controlling the bucking optimization works as expected, e.g. making it possible to change the mix of assortments or species harvested at a specific site.
Three harvesters reported the true position of the stem and most machines could report tracking data describing machine movements. All systems support registering “stem codes” that makes it possible to identity e.g. retention trees and wind-throws.
Other aspects such as precision of stem positioning, processing damages and sawing speed will be covered in other presentations at the conference.
| Keywords | harvesting; value-recovery; measuring; optimization; |
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