A new industrial chipper was designed for use in short-rotation forestry plantations, which requires high productivity and all-round mobility. The new machine was tested at seven different sites, representative of the main work environments negotiated by modern agroforestry contractors. The tests produced 114 chip containers, or 929 tonnes of fresh chips (ca. 3,500 m3 of loose chips). Productivity varied between 28 and 55 tonnes of fresh chips (or 105 and 194 m3 of loose chips) per productive work hour, excluding delays. Pure chipping productivity (calculated on chipping time only) was higher and peaked at 70 tonnes of fresh chips or 242 m3 of loose chips per hour. Fuel consumption ranged from 1.38 to 2.15 litres of diesel per tonne of green chips, or from 0.39 to 0.59 litres of diesel per m3 of loose chips. Machine utilization rate varied between 69 and 83%. Highest efficiency was reached at plant yards, due to optimum pile layout, wide space availability and easy chip discharge. Due to its remarkable off-road mobility, the new machine can restore efficiency to terrain chipping, provided that the terrain is flat and solid, the piles are duly arranged and a large enough support fleet is available for moving the chips to their destination.
Keywords: biomass; energy; productivity; fuel consumption; quality.