Optimal road spacing of cable yarding using a tower yarder in Southern Austria

Abstract

Cable yarding systems are widely used in mountainous forests of Austria. The goal of this paper is to determine optimal road spacing (ORS) of yarding operations by tower yarder in Styria to help logging planners minimize logging costs. A total of 591 working cycles were used to develop the multiple regression model using stepwise method to predict yarding time per cycle. The production and cost in whole tree uphill yarding were 6.70 m 3 / PSH and 27.60 Euro/m 3 , respectively. The roading, yarding and installation cost per cubic meter were computed for different yarding distances and graphed as a function of road spacing. The minimum total cost and ORS were 42.88 Euro/m 3 and 261 m, respectively for one-way yarding. For two-way yarding, the minimum estimated total cost, ORS and optimal road density would be 38.48 Euro/ m 3 , 373 m and 26.8 m/ha, respectively. The results showed increasing harvested volume decreases ORS and that increased roading cost increases ORS. The load volume has a significant effect on ORS.

Current possibilities of mechanized logging in mountain areas

“…Optimum network density is associated with the amount of wood to be obtained from one hectare, the cost of road construction and the size of a single load of harvested timber. Under the conditions in Austria, Ghaffariyan et al (2007) determined the optimal road density at 19.9 m/ha, with the following assumptions: average forwarder load -8.25 m 3 , harvested volume -100 m 3 /ha and road construction cost -20 EUR/m. Assuming that the machine will always skid a full load (17.5 m 3 ), the road density could be lower -13.5 m/ha.…”

“…With similar assumptions regarding harvesting and road construction costs, Ghaffariyan et al (2010) determined the optimal distance between roads in the event of skidding using the Wanderfalke tower yarder with a cable length of about 500 m. The results obtained for one-way and two-way hauling are 261 and 374 m respectively. The authors noted that harvesting costs for one-way uphill hauling drop sharply when the distance between roads increases from 20 to 230 m; while in the range from 230 to 290 m, they decrease only by 0.16 EUR/m 3 , which is an indication for those planning to modify a forest road network.…”

Efficiency of a Woody 60 processor attached to a Mounty 4100 tower yarder when processing coniferous timber from thinning operations

“…At the roadside, processing operations consist of tree delimbing, bucking, sorting and stacking of produced wood assortments (Borz et al 2011, Ghaffariyan et al 2009). While the roadside processing in case of such equipment does not affect the overall system's productivity (Ghaffariyan et al 2010), it may become signifi cant in the total fossil energy input since all the work elements performed here are mechanized. Yet, the avail-able information concerning the factors which affect the time and energy inputs generated by roadside processing using PTY technology is still limited, although the time consumed in such operations may be as high as 35-45% of the total yarding system time (Messingerová et al 2009).…”

“…In this context, a massive technology transfer was expected to countries having forest located in mountainous areas even if this kind of technology was less known at its appearing time (Heinimann et al 2001). However, being conditioned by a highly developed forest accessibility (Oprea 2008), and maybe due to the increased operational costs (Ghaffariyan et al 2010) the technology transfer has been slower, even in the case of developed countries (Matsuno & Koike 2012 (Borz et al 2011). On the other hand, when dealing with scientifi c studies addressing this kind of equipment, the situation is quite different since a lot of attention has been given by scholars to SY, TY and PTY forest equipment.…”

Road network optimization using heuristic and linear programming

“…He developed a model to define optimum road spacing based on minimizing the total cost of skidding and road construction from the viewpoint of a landowner. For downhill forwarding operation an ORS of 503 m was reported in Southern Austria (Ghaffariyan et al 2007). In two and three-stage cable yarding systems in British Colombia, three-stage yarding provided cost savings and a substantial increase in road spacing once critical road costs were exceeded (Howard, Tanz 1990).…”