The papermaking properties of 22 pure and hybrid poplars are being evaluated in an on-going investigation. Twenty of the poplars were harvested after 7.5 years from three different sites in the Midwestern and North Central US. The other 2 poplars survived at only two of three sites (64 total samples). The Crandon hybrid had the highest growth rate (t ha-1 y-1) and wood density (both averaged across the 3 sites). This poplar had a high cellulose content (compared to the average), a low lignin content and produced bleached kraft fibers at a high yield (wt.% on wood chips). Further, this poplar responded very well to kraft pulping and oxygen delignification and bleached to the highest final brightness ever observed in our laboratory (94.5% Elrepho). It also produced an 18 kappa number unbleached pulp with <0.5% rejects in only two-thirds the time required for sugar maple (Acer saccharum). We also report on clone 220-5 that had the highest area-weighted average microfibril angle. Pulps from this poplar had excellent tensile properties and further improvements are expected with 1-2 years of additional growth that should result in a small, but significant increase in average fiber length. Some results are also presented for clone 313.55 and aspen (Populus tremuloides) to demonstrate the many substantial benefits that can be accrued from proper wood selection.
Bibliographical noteFunding Information:
The financial support from the US Forest Service Grant ♯SRS-03-DG-11330103-033 and 03-JV-11231300-048 and the member companies of ESPRA is deeply appreciated. Although compensated, we are still very thankful to Dr. Geoffrey Downes and his colleagues at CSIRO Forestry and Forest Products, Tasmania, Australia for their determinations of microfibril angles. We are also grateful to two of our undergraduate students, Mr. Nourredine Abdoulmoumine and Ms. Nataliya Lavykova for their technical assistance.
- Fiber properties
- Kraft pulps
- Microfibril angle