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Research has examined the productivity, energy inputs and emissions of mini-skidders in thinning operations.A rubber-tyred mini-skidder (Ecotrac 55V) with dual winches was used to extract timber on two sites, the first being a thinning operation and the second a regeneration cut. The skidder extracted half-processed assortments. The sites consisted of mixed stands of Quercus, Fagus, Carpinus, Tilia, Robinia and other broadleaves. The average DBH of the trees on the first site was 23.46 cm, and 33.19 m3 was removed per hectare (of a possible 203.17 m3 per hectare). The average DBH of the trees on the second site was 45.32 cm, and 125.47 m3 was removed per hectare (of a possible 582.06 m3 per hectare).
The results showed that the mini-skidder was capable of productivities of 3.2 m3 per machine hour at the first site and 4.95 m3 per machine hour on the second site. This was expected due to the bigger tree size and increased volume being removed at the second site. The average extraction distance for the first site was 210 m and for the second site was 260m. This is relatively far considering that the average payload for site one was 1.037 m3 and for site two was 1.191 m3. At the first site, both winches were used 77% of the time, while at the second site both winches were used only 16% of the time. The first site also had a steeper slope than the second site (17% versus flat). The slopes at site one resulted in higher fuel consumption than site two, and the fuel use is comparable to other studies into machines used under these conditions.
The research results were published in the journal of Ecological Engineering, 61 (2013). The title was “Skidding operations in thinning and shelterwood cut of mixed stands – Work productivity, energy inputs and emissions”. The authors were D Vusic, M Susnjar, E Marchi, R Spina, Z Zecic and R Picchio. Source: http://www.sciencedirect.com/science/article/pii/S0925857413003984