The interaction between off-road vehicles and terrain in forestry operations has been extensively studied to assess machine performance and soil damage, emphasizing the importance of the relationship between machine mobility and terrain conditions. This study assesses the rolling resistance coefficient (mu r) using engine data acquired through CAN-bus systems and the J1939 standard. The aim is to determine whether soil-machine interactions can be detected by modeling rolling resistance coefficients with a simple approach based on machine parameters and essential terrain characteristics. The study was conducted on a forwarder (John Deere (R) 1210G) across different terrain surfaces and load conditions. CAN-bus data were processed, while terrain characteristics and slope were determined using high-accuracy spatial data. The activities consisted of (i) a calibration test to evaluate the model's sensitivity and (ii) a field test in a real working scenario. The developed methodology demonstrated sufficient sensitivity to detect increasing rolling resistance values on rougher surfaces, highlighting the impact of surface type on forwarder operations. Field tests revealed lower rolling resistance values for the unloaded forwarder (between 0.15 and 0.3) than loaded conditions (from 0.4 to 0.6). The model reliably captured mu r changes between consecutive drives and skids, particularly during uphill operations, with significant differences influenced by trail conditions and forwarder interactions rather than just load. By providing a practical methodology for assessing off-road machine performance and its impact on driving surfaces, the study highlights the importance of understanding off-road vehicle dynamics for informed operation planning decisions. This study underscores that integrating real-time mobility data from CAN-bus technology with terrain analysis enhances operational efficiency and helps minimize soil damage, thereby supporting more sustainable forest management practices.

Protecting soils during forest operations is important, especially soils with limited bearing capacity that are being harvested during the wet months. These soils can sustain damage to their structure, and therefore site productivity can be reduced. Climate change may change weather patterns, and less frozen soil conditions will occur more frequently, forcing planners to search for alternatives to overcome this challenge. In this context, cable-based systems for tree yarding are one option to reduce potential damage to soils and remaining stands. Time studies were performed on three cable yarding operations in the canton of Aargau, Switzerland, aiming to understand the performance of cable-based systems in flat terrain. A statistical analysis was performed, and costs were calculated. The yarding productivity was 13.92-21.86 cubic meters over bark (m3ob) per productive machine hour. The payload was identified as the main variable significantly influencing the productivity of a yarding cycle. Overall, installation procedures of the yarder were the most time-consuming and expensive work step. Production costs were 70-102 CHF m3ob-1 (corresponding to 73-107 euro m3ob-1), including felling, yarding and roadside processing. This study confirms that the costs resulting from cable-based operations in flat terrain are high and the approach is not (yet) competitive with ground-based systems.

The disturbance that ground-based extraction operations can imply on the forests ecosystem is an issue which demands more attention. Skidding and forwarding are the two most common ground-based extraction systems. While skidding implies to partially or fully dragging the logs on the ground, in forwarding, timber is transported on a deck thus avoiding direct contact with the soil. Generally, skidding is considered to be more impactful than forwarding in relation to the amount of disturbance on forest soil and residual stand. However, the framework depicted in current literature is not so strict. While skidding actually implies a higher level of damage to residual stand, the situation concerning disturbance to forest soil is much more complex. The dissimilarities in the results from various studies on this topic have shown the level of complexity. The lack of research investigating the consequences of the two extraction systems on the overall forest ecosystem is evident. Only a few studies were focused for example on the implications on biodiversity. However, the beneficial effects of best management practices, such as the application of snatch blocks during winching or positioning brush mats on the skid trails/ strip roads to reduce soil compaction, have been clearly demonstrated.