Kraft Pulp Yields and Paper Properties Obtained from First and Second Rotations of Three Hybrid Poplar Clones
Keywords:Kraft, paper properties, poplar
Studies indicate that short rotation intensive cultured (SRIC) Populus hybrid clones could be utilized as wood source for some paper grades. However, to take advantage of the SRIC system, acceptable pulp yields and paper properties must be obtained from subsequent tree rotations. Therefore, a study was undertaken to evaluate and compare the kraft pulp yields and paper properties obtained from first and second rotations of three Populus hybrid clones harvested at three years of age.
No significant differences (P ≤ 0.05) in total kraft pulp yields were measured between first and second tree rotations, although slightly higher yields were consistently obtained from all three clones of second rotation trees. Comparisons of handsheet strength properties between rotations showed significant improvements in handsheet tensile properties for clones 50 and 252 and handsheet tear for clone 252. Strength improvements for these clones may, in part, be attributed to improved fiber characteristics obtained from sprouts regenerated from stumps as opposed to vegetative propagation.
Difficulties in paper machine operation can possibly be encountered because of the preponderance of fines and debris found in both first and second rotation of juvenile Populus hybrid total tree pulp. Initially, low freeness levels (CSf) with minimal refining indicate that some adjustments for paper machine operation may be necessary to accommodate this type of pulp in the furnish.
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