Shape of skidder productivity function for ground based skidding system in Caspian forests

Abstract

Understanding how stand and terrain parameters impact the productivity of harvesting machines is important for determining their optimum use. Time and motion studies were conducted to evaluate the impact of terrain characteristics and work methods on skidder productivity in cut-to-length skidding system in easy and difficult terrain condition in Caspian forests. It was found that the productivity for skidding operation on selective cutting sites classified as easy and difficult terrain conditions, ranged from 18.22 to 14.25m 3 h -1. The results proved that logarithmic model in both skidding distance (R 2 =0.61 and Y=-11.97ln(x)+78.383) and volume per turn (R 2 =0.53 and Y=10.058ln(x)+10.1580) entered in the model in easy condition. Also, the results proved that the logarithmic model in both skidding distance (R 2 =0.32 and Y=-6.874ln(x)+47.604) and volume per turn (R 2 =0.37 and Y=14.874ln(x)+1.2241) entered in the model in difficult condition. These observations suggest that maximization of payload and optimization of timber extraction distance are more crucial for economic skidding on difficult sites. Also, skidding in easy terrain condition can increase productivity until 3.97m 3 h -1 . It can be concluded that correct design of skidding trails can resulted in more production during ground based skidding in the region.

Optimizing Forest Harvesting Efficiency: A Comparative Analysis of Small-Sized Logging Crews Using Cable-Grapple Skidders

“…Skidding distance, load volume, and number of stems, often combined, have been frequently identified as factors exerting a significant impact on time consumption during skidding operations. Skidding distance has been a consistent component of all productivity-and cycle time-related models in the present study, as well as in previous research (e.g., [7,[25][26][27]). Load volume was found to impact effective skidding cycle time (Model 1), net productivity (Model 4), and gross productivity (Model 5), which is a finding also consistent with the findings of Orlovský et al [25].…”

“…These values are considerably higher than those in our case and may be attributed to the much shorter skidding distances. Behjou [27], after examining beech wood extraction in Iran, reached the same conclusion and reported a productivity of 34.97 m 3 PMH −1 declining to 11.22 m 3 PMH −1 for the skidding distances of 50 m and 425 m, respectively, with the rate of productivity decline being higher for lower skidding distances.…”

Optimal Forest Road Density as Decision-Making Factor in Wood Extraction

“…Consequently, this variation interfered with the extraction distance and displacement times. In addition, extraction trail conditions, terrain slope, remaining stumps, harvesting residues, and wood extraction volume may have impacted operating cycle time [71][72][73].…”

Methodology for Assessing and Managing the Environmental Performance of Skidding and Feller Buncher Tractors

“…Factors influencing the environmental efficiency of skidding tractors can be grouped as follows: changes in physical and mechanical properties of soils in the felling area, the impact on undergrowth, and environmental pollution (Figure 3). The skidding tractor's operational efficiency scheme developed in [21] was complemented by factors affecting environmental efficiency. When the methodology adopted in the study of mobile systems is combined with an inclusive approach, the operation of a skidding tractor can be depicted as a system object.…”

“…The system of indicators and factors specifying the operating conditions of a skidding tractor is illustrated in Figure 1, and its service properties and operational effectiveness are presented in Figure 2 [20]. The skidding tractor's operational efficiency scheme developed in [21] was complemented by factors affecting environmental efficiency. When the methodology adopted in the study of mobile systems is combined with an inclusive approach, the operation of a skidding tractor can be depicted as a system object.…”