Speakers
Description
Cistus laurifolius (rockrose) biomass was harvested in a mechanised operation at CEDER-CIEMAT (Cubo de la Solana, Soria, Spain; mean internal transport distance for the harvested biomass ≈3.50 km round trip). The work was carried out in six plots grouped into two age classes (three young-rockrose plots and three old-rockrose plots), allowing performance and losses to be reported separately for each stand type while keeping an overall operational approach. Harvesting was performed with a Valtra T194D forestry tractor (154 kW) equipped with reverse-drive (TwinTrac) and forestry protections, operating a López Garrido TBA 2300 shredder-harvester powered by the PTO and fitted with swinging hammers. During operation, the implement cuts and shreds the shrub layer. The shredded material is moved to an on-board tipping container coupled to the tractor, where the load is accumulated. The container has a nominal capacity of 5 m³; in day-to-day operation, a typical full load was around ~1,000 kg of fresh biomass (field estimate). Once filled, the unit travels to the unloading point and the biomass is discharged by tipping the container. This work pattern integrates cutting, comminution, loading and internal transport with a single operator, and time study/recorded operational times allow productivity to be expressed both for harvesting time only and for total operational time including travel and delays.
Across all six plots, total recovered production reached 23.5 t of dry matter (tDM). Average productivity was 1.52 tDM h⁻¹ when considering harvesting time only, and 0.76 tDM h⁻¹ when total operational time is accounted for (including travel and delays). Area-based recovered yield differed strongly by stand age: 3.82 tDM ha⁻¹ in young rockrose and 8.38 tDM ha⁻¹ in old rockrose (overall mean 4.78 tDM ha⁻¹). In addition to recovered biomass, two loss components were quantified: “unharvested” biomass (material left uncut due to operational or geometric constraints, such as very low material or inaccessible stems) and “lost” biomass (material that is cut but not recovered and therefore does not reach the container). In old rockrose, mean unharvested losses were 0.52 tDM ha⁻¹ and mean lost losses were 1.91 tDM ha⁻¹; expressed as a share of the considered total potential (recovered + losses), these represent 4.8% and 17.7% respectively, with 77.5% effectively recovered. In young rockrose, mean unharvested losses were 0.27 tDM ha⁻¹ and mean lost losses were 0.82 tDM ha⁻¹; as percentages of total potential, they account for 5.6% and 16.6%, with 77.8% recovered. These values indicate that the dominant inefficiency is associated with post-cut recovery rather than with the fraction that remains uncut, and they provide a quantitative basis to prioritise improvements in the harvesting head and in operational logistics (unloading and internal hauling), which directly influence the difference between harvesting-time productivity and total-time productivity.
| Keywords | Shrubland, biomass, harvester, cistus |
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