FIRST THINNING IN A CONIFEROUS PLANTATION FOR BIOMASS PRODUCTION: PRODUCTIVITY AND COSTS

This paper deals with the study of mechanized yard for the thinning of a coniferous plantation (Pinus halepensis and pinaster). The systematic selective thinning was adopted with a 50% trees removal. The final product was chips for energy use. The machines used were: one harvester for trees felling and bunching, one agricultural tractor with log grapple for trees extraction, one forest loader and one forwarder with chipper for trees chipping. The gross productivities for felling and bunching was of 23.4 t/h, for skidding 21.7 t/h and for chipping 46.5 t/h. The cost per unit of mass product (chips) was about 14.94 !/t. Considering the stumpage (10.00 !/t), the transfer machines (2.09 !/t) and transport (13.00 !/t) the total production cost of chips was 40.03 !/t. The results, compared with a market price of the chips 50.00 !/t, underline the light economics sustainability of thinning.