Variability in Pulping and Fiber Characteristics of Hybrid Poplar Trees Due to Their Genetic Makeup, Environmental Factors, and Tree Age, 1997 Pulping Conference Proceedings

Variability in fiber and pulping characteristics caused by the genetic makeup of five hybrid poplar clones was investigated. Specific gravity for the five varied between 0.30 to 0.36. Pulp yield varied significantly (49-57%). Variation in pulp yield correlated well with the alpha-cellulose content of the wood. Higher yield did not always translate into higher pulp production due to differences in specific gravity (digester packing). Strength properties (tear and tensile) also varied significantly among clones. The drier and warmer growing environment found in northeast Oregon where irrigation was required yielded trees with slightly longer fiber and higher specific gravity and pulp yield (3-4%), as compared to trees of the same clone grown in the cooler, wetter environment typical of western Oregon. Effect of tree age was investigated by separating and characterizing wood from each annual ring. It was found that fiber length, pulp yield and tear index at a given tensile index increased with age.