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Research article - Peer-reviewed, 2021

The impact of using different wood qualities and wood species on chips produced using a novel type of pilot drum chipper

Timmerfors, Jessica Gard; Salehi, Hamid; Larsson, Sylvia H.; Sjolund, Torbjorn; Jonsson, Leif J.


Resource-efficient wood chipping for forest-industrial processes demands large fractions of accept chips and small fractions of small-sized material, such as pin chips and fines. In Kraft pulping, a narrow distribution of wood chip thickness is important for even impregnation and for making high-quality pulp. Using newly developed forest-industrial drum-chipping technology, the investigation covered wood of varying moisture content, frozen versus unfrozen wood, and the use of different wood species. Using conventional techniques for analyzing wood chip dimensions, fast-grown spruce wood with high moisture content gave 4.2% pin chips and fines, which was less than half of the fractions obtained with spruce wood with lower moisture content. A comparison between frozen and unfrozen pine resulted in slightly thinner and shorter chips for the frozen wood, but in both cases accept yields of up to similar to 85% were achieved. A comparison of different tree species (aspen, birch, pine, and spruce) resulted in larger accept fractions (similar to 90%) for the hardwood species, even though the average length of these wood chips was as low as 17 mm. The results provide a first indication of how basic wood log properties affect the yields of accept chips and small-sized material when using modern industrial drum-chipping technology.


drum chipper; frozen wood; moisture content; tree species; wood chips

Published in

Nordic Pulp and Paper Research Journal
2021, volume: 36, number: 2, pages: 214-226

Authors' information

Timmerfors, Jessica Gard
Umea University
Salehi Kahrizsangi, Hamid
Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology
Swedish University of Agricultural Sciences, Department of Forest Biomaterials and Technology
Sjölund, Torbjörn
MoRe Research Örnsköldsvik
Jonsson, Leif J.
Umea University

UKÄ Subject classification

Wood Science

Publication Identifiers


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