The impact of a small forwarder with the wheeled chassis, tracked-wheel chassis, and tracked chassis traveling on the soil profile was studied. The three chassis types were assessed for the influence of the loading of forwarder cargo space and the degree of tire inflation on induced specific and actual pressures of tires on the soil surface. Penetrometric resistances of soil profile and rut depths in the forwarder driving track were measured. The effect of a layer of logging residues in the forwarder driving track on the size of induced actual pressures was determined. The practice of determining the impact of forest machines on the soil surface by means of a specific tire pressure does not have a full informative value. In the forwarder wheeled chassis, maximum values of actual pressures exceeded specific pressures established numerically by up to 203%. Average values of actual pressures could be reduced by 45% by reducing the pressure of tire inflation, by 70% with the use of tracks, or by 49% by traveling on the layer of logging residues. As compared with the wheeled chassis type, the tracked type of the forwarder chassis induced actual pressures to lower by 81% and the rut depth after ten forwarder passes was smaller by 50%.

This paper deals with the use of debarking modifications of the conventional harvester head in the conditions of felling due to bark beetle calamity. For this purpose, a time study was established, in which the conventional heads were compared with the heads with debarking modifications on four research plots and two harvesters. The measurements were taken from August to September 2018. Harvester efficiency with the use of the head with the debarking configuration ranged from 41.2% to 41.8% from the efficiency of a machine with the conventional head, depending on the felling type. It was also demonstrated that the quality of debarking does not depend on the trunk moisture content in the growing season. In terms of diameter, it was found that the best debarked parts of the stem were those occurring in its middle. Specifically, in the central part of the stem with a diameter of 13 to 23 cm, 91.0% of the stem area was debarked in the main felling and 76.6% in the thinning. In contrast, the top parts of the stem (trunk diameter up to 13 cm) were the least debarked. In the main felling, it was 74.2% of the stem area and in the thinning, only 52.2%.

This paper deals with the influence of an Intelligent Boom Control (IBC) in forwarders on the work of operators. The work with the IBC and standard system of crane control was measured by the use of a John Deere harvester and forwarder simulator. Two individuals without any practical training and two individuals with experience in the control of the crane took the measurements. The monitoring included eight different performance indicators. The use of the IBC system allowed the untrained operators to increase their work output by 27. With the use of the IBC system, these individuals also showed 53% fewer direct damages to the machine. However, our findings show that the length of experience influenced the performance of the operators out of all the monitored indicators. Notwithstanding that fact, the use of the IBC system has a direct positive influence on the economy of the machine operation.

Plantation forestry has a long history in Europe and still supports local industry, generating employment, improving environmental quality, and mitigating climate change. As part of these plantations, medium-rotation poplars (5–8 years) provide good quality logs for fiber production, and the branches and tops can be converted into green energy. Finding a cost-effective harvesting system for this plantation is challenging due to the small tree size and the need for log production, which prevents whole-tree chipping. To verify the economic benefit of using small mechanized cut-to-length (CTL) technology, four different CTL chains were tested in western Slovakia. All chains tested consisted of a harvester and a forwarder. Each machine had a skilled operator and was timed while cutting and processing (or forwarding) eight experimental sample plots. Sample plots were randomly assigned to each treatment, and each one covered an area between 0.08 and 0.10 ha (120–170 trees). Harvester productivity ranged from 2.2 to 4.2 bone-dry tons per scheduled machine hour (BDT SMH⁻¹), and harvester cost from EUR 11 to EUR 22 BDT⁻¹. Forwarding productivity and cost ranged from EUR 2.0 to 4.5 BDT SMH⁻¹ and from EUR 9 to 20 BDT⁻¹. Total harvesting costs ranged between EUR 26 and 36 BDT⁻¹. Choosing a smaller harvester is preferable due to the small tree size, which caps productivity regardless of a machine’s intrinsic potential. Furthermore, small harvesters and forwarders are lighter on the ground, which can be a valuable asset on the many wet sites planted with poplar.

This paper deals with the verification of models for the calculation of the contact area with the soil using data measured during the testing of a tractor-and-trailer unit. The main emphasis was put on the method of calculating the contact are...