Towards more sensitive forest operations– TECH4EFFECT conducted field trials with forwarders and flotation tracks

The TECH4EFFECT (Knowledge and Technologies for Effective Wood Procurement) project successfully conducted field trials near Rautavaara, Finland, on the impacts of different tracks and machines on the soil. The field tests were conducted during the last week of June 2019 by the project partners Luke, NIBIO and Ponsse in cooperation with contractors and their operators as well as Metsähallitus.

Eight researchers, four operators and representatives of Ponsse were working on the site in soft soil peatland. The researchers conducted measurements on the soil and on the machines.

The aim of the field test was to study the effects of different machine and track combinations on wheel rut development and fuel consumption on soft soil.  5 different track types were tested. The impact was measured as the depth of any ruts developed over multiple passes, both while driving straight and through a curve of 20 m radius.  The trial was also used to evaluate different methods of measuring soil displacement, including a horizontal laser and measuring stick, a personal laser scanner (PLS) fitted on a backpack,  and the use of a digital surface model from derived from an unmanned aerial vehicle (UAV) flown at low altitude.  Results of both the track and machine combinations, and the measurement methods will be analysed and disseminated in autumn.

Ponsse forwarder loading

Ponsse 8-wheeler Wisent forwarder loading during thinning operations in Joensuu, Finland

Field trials: Cable-assisted timber harvesting on steep terrain

In cable-assisted timber harvesting forces on the cable are enormous. But how strong exactly are they?

As part of TECH4EFFECT WP3 , Markus Engel and Andreas Mayerhofer (ÖBf – Austrian Federal Forests ) and Thomas Holzfeind from BOKU carried out investigations on winch assisted harvesting machines in the ÖBf forest district Flachau (Austria). They recorded the inclination of the machine during operation on steep terrain using a tilt sensor installed on the winch assisted Valmet 840TX forwarder. At the same time, the tensile forces in the cable were measured with a load shackle. In addition, all activities of the machine were recorded by an action camera, which will be analysed later together with inclination data and the tensile forces. The results are intended to shed light on the tensile forces that occur in the cable of the machine as a function of the work processes and the machine inclination.


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Cable assisted forwarder operating on steep terrain; pictures: Holzfeind Thomas