Strip thinning in a Quercus cerris coppice stand: comparative trials between six working systems with different extraction methods.
Trials were carried out in 1979 in a 16-yr-old stand on hilly ground in Grosseto district, central Italy, as a first step in the conversion of the crop to high forest. Parallel, linear strips 4-m wide were clear felled in the direction of the slope. Belts of uncut coppice 8.5-m wide were left between the strips. Six skidding systems were evaluated: (1) traditional haulage with mule or horse of 1-m bolts; (2) 2-m bolts, hand loaded on to a 2-wheel-drive trailer towed by a 70-hp agricultural tractor; (3) as in (2), but using a small 45-hp forwarder; (4) skidding 3-m bolts, hooked in bunches, with a frame-steered 52-hp skidder; (5) skidding tree-length stems as in (4); and (6) skidding entire trees, with branches, as in (4). With an extraction distance of < 500 m, systems (5), (3) and (2) gave the highest output of roundwood (24, 21 and 21 t/day respectively over a 300-m haul). Over longer distances systems (2) and (3) gave the highest output (16 t/day vs. 14 t for system (5), over an 800-m haul).