Fiber length characteristics of Norway spruce (<i>Picea abies</i>) trees with fast height growth

Abstract Pulp fiber lengths are important in the mechanical behavior of paper and paperboard materials. The length affects the total number of bond sites in fiber networks and thus indirectly the paper strengths. In a case study at Mölnbacka Sweden, fiber lengths of wood samples from 38-year-old trees of Norway spruce ( Picea abies ) with fast height growth were investigated. The fiber length of the samples was compared with literature values, and some reference example material. The hypothesis was that the sampled trees with fast height growth may have longer fibers, and thus provide longer pulp fibers, compared to lengths previously reported. The work highlights and critically examines the impact of different preparations, measurements, and analysis methods of fiber lengths. The results from this study show that the 21-year-old sampled wood had longer fibers than expected when compared to previous reports for Norway spruce wood grown in Sweden. The samples also showed to have skewed distributions with proportionally more long fibers than expected, also shown by higher mode values to describe central tendencies. About 75 % of the manually measured Mölnbacka fibers were longer than 3.1 mm with a mode value of 3.77 mm.