Preliminary data on the productivity of stump lifting head MCR-500
2012
Lazdins, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Zimelis, A., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Gusarevs, I., Orvi, SIA, Salaspils (Latvia)
The first published studies on stump extraction for bioenergy in Latvia are dated with second half of the 19th century. In the 3rd decade of the 20th century, stump extraction was identified as one of the most prospective and challenging tasks of forest sector to secure sustainable deliveries of solid biofuel. In that time, stump extraction using explosives was considered to be a conventional forestry technology. Now we are returning to the same challenges; however, mechanical power is used instead of explosives to pull and to crash stumps. MCR-500 is the first prototype of combined stump extraction and mounding head for a caterpillar excavator produced in Latvia by joining forces of the LSFRI Silava and engineering company Orvi SIA. The device is supposed to be used for extraction of stumps with a diameter up to 50 cm in coniferous and deciduous tree stands. Additional benefit of the device is ability to prepare soil by making mounds for the following forest regeneration. The article summarizes results of productivity trials of stump extraction and preparation of soil using the MCR-500 head. In total, 3.5 ha were extracted during the studies. The harvested amount of stumps was estimated using biomass equations; therefore, it might be corrected in further forwarding and comminution studies when an actual amount of biomass is estimated. Average stock of extractable biomass (stumps and coarse roots) in the experimental sites was 28 tons ha-1. Productivity of stump extraction was 2.4...3.4 tons per efficient hour (2.5 tons in case of optimal rate of scarification of soil). Consumption of efficient time for scarification of soil is 3.4...4.3 hours per ha. Figures of productivity of stump extraction are comparable with the ones obtained with similar stump extraction heads. Scarification of soil with stump lifting head consumes twice more time than conventional trenching; however, in wet sites, productivity figures become closer making the excavator competitive.
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