|Abstract or Summary
- A study has been made of the kraft pulping properties of young Douglas-fir trees which were thinned from an experimental plantation. The purpose of the plantation study is to determine, whether two year old seedlings can be selected on the criteria of height and branch count for future desirable tree and utilization characteristics. The trees used in this experiment were 15 years old at the time of cutting. They were all pulped by a standardized kraft process, and the pulp evaluated according to TAPPI Standards. The test results were evaluated by an analysis of variance computer program at certain discrete refining intervals, 600, 400, and 200 Canadian Standard Freeness, and 0.7 and 0.8 gms/cc sheet density. The trees grown from seeds germinated in the Corvallis nursery were, as a class, taller and larger in volume than their counterparts from the Salem nursery. Significant differences in tensile and bursting strengths, properties important to the linerboard industry, were found between these two classes of pulps, with the Corvallis pulps stronger than the Salem pulps. Lesser differences in these two properties were found when the pulps were classified according to the branch count of the parent trees, and no significant difference could be attributed to the tree height (Control vs. Super Seedlings) criteria. The differences in the other pulp characteristics were found to be non-significant by any of the criteria of tree classification. Two factor analysis of the pulp properties within nurseries disclosed no significant differences within the Corvallis nursery trees, but substantially more significant differences within the Salem nursery trees. The inference is that both pulp properties at age 15 and branch count at age 2 are predominantly influenced by hereditary factors. Tree height at age two is less influenced by heredity than branch count. Overall, the differences in pulp quality between the tested trees are small, which is not surprising in view of the high proportion of juvenile wood and the relative lack of differentiation. Larger differences may be apparent when the trees are older. The pulp properties compare favorably with those of other Douglas-fir kraft pulps prepared at the Forest Research Laboratory, but the influence of the juvenile fibers can be detected in this comparison also.