Assessment of Working Performance and Costs of Two Small-Scale Harvesting Systems for Medium Rotation Poplar Plantations

Abstract

Considering the increasing need to produce energy from renewable sources, the interest towards Medium Rotation Coppices (MRC) plantations has increased. One of the main issues that require tackling for the comprehensive sustainability of these plantations is related to the development of sustainable harvesting systems. Indeed, as a consequence of the average tree diameters at a breast height (dbh) of about 15 cm, single-pass harvesting typical of short rotation coppice is not applicable. Therefore, these plantations are generally harvested with machinery specifically developed for forest operations, as for instance harvesters, feller-bunchers and forwarders. In the Mediterranean area, the availability of such machines is still limited to a few big forest enterprises. Indeed, the majority of forest contractors carry out their activities in the framework of small-scale forestry, without the financial possibility of purchasing expensive machineries. Thus, the present study had the objective to evaluate the performance of two small-scale harvesting systems in a 7-year-old poplar plantation in Central Italy. The difference between the two systems was the different machinery applied for wood extraction, i.e., a forestry-fitted farm tractor equipped with winch (WINCH) and a fork lift prototype, attached to a crawler tractor (CFL). Extraction via CFL system reached very high working performance with about 21.5 m3 SMH−1 (Scheduled Machine Hours, including delays), comparable to the productivities reported in the literature for forwarders working in similar plantations. Harvesting costs with CFL were 24.74 EUR m−3, of which 4.48 EUR m−3 was for felling with chainsaw, 4.61 EUR m−3 for extraction with CFL prototype and 15.64 EUR m−3 for wood chipping. WINCH showed unsatisfactory results instead, possessing a wood chip production cost of 41.95 EUR m−3, which is practically equivalent to the market price of wood chips.