extraction over long distance without driving on the ground
extracting in steep terrain (uphill)
bringing trees to a site where machines for delimbing and cross-cutting can operate
Limitations, threshold
distance limited by the length of the cable, often more than 100 m
distance limited by the weight of the cable that must be pulled by the worker, so on flat terrain not more than 50 m, downhill wider distances are possible
cable cannot be pulled uphill, therefore no downhill extraction over longer distance
Main use
in stands where fully mechanized methods are not applicable due to ground conditions, tree species (large broadleaf trees, e.g.)
with wider distance of trails, where trees must be pulled into the reach of the crane of a machine
in combination with extraction by means of a tractor
When pre-skidding distance increases from 20 to 60 m (i.e. triples), then productivity decreases between 40 and 70% and pre-skidding cost increases up to 2.5 times. The effect of pre-skidding distance is stronger with smaller tree volumes.
When tree volume increases from 0.1 to 1 m3 (i.e. factor 10), then productivity increases between 50 and 180% and pre-skidding cost decreases between 33 and 66%. The effect of tree volume is stronger on shorter distances.
Example:
machine costs without personal
costs: 10,00 Euro/h
Since winchpre-skidding is extremely sensitive to distance,
it should be used on very short distances, only. If tree volume is large
enough, then one can obtain acceptable results also on medium distances, up to
50 m.
E-class: simple machine work, heavy and dangerous -> E3
Literature:
Dekking J. 1984 Goliat, a small tractor with
tracks. IEA/FE/CPC7 Report, 17 pp.
Dunnigan J. 1993 Braided KevlarTM
Cable: Trials in Skidding Wood With an ATV. Field Note FN-022. FERIC. Pointe
Claire, Quebec, Canada.
Ewing R.
2001 Use of a portable capstan winch and associated hand tools in manual
thinning. FERIC Advantage Reports, 28: 4 p.
Ewing R.
2003 Harvesting riparian zones using cable skidders equipped with Spectra
synthetic-fibre mainlines. FERIC Advantage Reports, 20: 6 p.
Harstela P., Tervo L. 1981 Bunching of timber by
winches and horse. Folia Forestalia 466, 20 pp. In Finnish.
Hill S. 1991 D4H tractor and towed arch in
radiate clearfell. LIRA Report 16, 8. 4 p.
Horvat D,
Spinelli R, Šušnjar M. 2005 Resistance coefficients on ground-based winching of
timber. Croatian Journal of Forest Engineering 30: 3-11
Leek N. 1976 Bunching with Radiotir 740 in
thinnings. Nederlands Bosbouw Tijdschrift 48: 151-157.
Magagnotti
N., Spinelli R. 2012 Replacing steel cable with synthetic rope to reduce
operator workload during log winching operations. Small Scale Forestry 11:
223-236.
Picchio
R., Magagnotti N., Sirna A., Spinelli R. 2012 Improved winching technique to
reduce logging damage. Ecological Engineering 47: 83-86.
Prebble
R. 1986. Evaluation of the Logquip smart arch. LIRA Report 11, 5. 4 p.
Pritchard
N. 1986. The Logquip smart arch for small crawler tractors. LIRA Report 8. 4 p.
Ryans
M. 1980 Evaluation of the Agri-Winch: a farm tractor-mounted logging winch.
FERIC Tech. Rep. TR41. 18 p.
Spinelli
R, Magagnotti N 2012 Wood extraction with farm tractor and sulky:
estimating productivity, cost and energy consumption. Small-scale Forestry 11:
73-85.
TDB 2002
ATC timber sulky. Information Note ODW 9.04, Ae Village, UK. 5 p.
Turner T., Huyler N. Bousquet D. 1988 Farm
Tractor Skidding Costs in Relation to Profitability of a Fuelwood Harvesting
System. Nort.h J Appli For 5: 207-210
Vaughan L. 1988 Thinning with small crawler
tractors. LIRA Report 13, 26. 6 p.
Zeĉić Z., Krpan A., Vukuŝić S. 2005
Productivity of Holder 870 tractor with double drum winch Igland 4002 in
thinning beech stands. Croatian J For Eng 26: 49-56.
