Thesis (M.S.)--Oregon State University, 2000. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

Thesis (Ph. D.)--University of Chicago, 1911. / "Reprinted from the Botanical Gazette, Vol. LV, No. I." Also available on the Internet.

Inaug. diss. - Munich, 1933. / Lebenslauf. "Literatur verzeichnis": p. [81]-84.

Thesis (M.S.)--University of Wisconsin, 1964. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 33-34).

This study was designed to throw some light upon the nutritional requirements of certain commercially important species of the western coniferous forests of Canada. Five species, coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii), interior Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca), Engelmann spruce (Picea engelmannii (Parry) Engelm.), ponderosa pine (Pinus ponderosa Dougl.) and western white pine (Pinus monticola Dougl.) were grown in sand cultures in a greenhouse and artificially subjected to macro-nutrient deficiency for a period of nineteen months. The quantitative effects of such deficiencies on shoot and root growth, shoot/root ratios, chlorophyll content, vigor, specific gravity of the wood, foliar content of reducing sugars and foliar content of copper and zinc were studied and described. Chlorotic and necrotic symptoms were compared with the use of a coded color chart and keys to the various deficiencies constructed on the basis of these color comparisons. The foliar symptoms of deficiency were completely documented by color photography. A concurrent study of the growth of the same five species on four different soil types was also undertaken. Apart from affording useful information on the suitability of the soils for the growth of the species studied, this portion of the experiment confirmed the fact that the sand culture technique is an acceptable experimental method for growing conifers. The concept of tolerance was discussed and a method proposed for its objective determination. In essence, then, this study established a dependence between five coniferous species and an adequate supply of macrometabolic elements for normal development and growth. The imposition of deficiencies of any one of six elements studied resulted in reduced growth and arrested development. Quantitative and qualitative confirmation is given of the reality of these effects. / Graduate and Postdoctoral Studies / Graduate

The hypothesis is examined that short-term creep response of earlywood and latewood tissues of some coniferous species, stressed in tension parallel to the grain, is a function of microfibril angle of the S 2 layer of and relative degree of crystallinity in the tracheid cell wall, along with specific gravity of that wood tissue and its extractives content. A new technique was developed to measure the total creep that occurred over a 60-minute period of time for small specimens (nominally 0.010 in, thick) of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) (normal and compression wood), Sitka spruce (Picea sitchensis (Bong.) Carr.) and western hemlock (Tsuga heterophylla (Raf.) Sarg.), taken from earlywood and latewood zones of the same increment. Total creep was determined at two initial deformation levels, 3,000 microin.per in. (strain level No. 1) and 6,000 microin. per in. (strain level No. 2). Microfibril angle was measured by a modified mercury impregnation method, while cell wall crystallinity was determined on small, unoriented pellets by the X-ray diffraction technique. Air-dry specific gravity (oven-dry weight) and alcohol-benzene plus hot water extractives were also determined by conventional methods. Multiple regression analyses were carried out and prediction equations, based on the experimental results, have been constructed. It is shown that the variability in total creep response can best be explained by using the prediction equation which contains microfibril angle of the S2 layer, specific gravity and extractives content. The multiple coefficients of determination (R²) using this subset of variables are 0.7680 and 0.8550 for initial strain Numbers 1 and 2, respectively. Cell wall crystallinity was eliminated from the prediction equations as the least important variable due to its high inverse correlation with the microfibril angle of the S2 layer (r=0.9284). Two possible reasons are suggested to explain this correlation. First, in the case of a small angle, the scatter around the mean microfibril angle is smaller and the microfibrils probably lie almost parallel to each other. As a result, the relative degree of amorphous material required to fill the micro-spaces between microfibrils would be smaller. Considering the case of a large microfibril angle, the microfibrils are probably not parallel to each other; consequently, relatively large micro-spaces would be occupied by the amorphous material. A second possible reason for this relationship may be that cellulose chain molecules, in the case of a small microfibril angle, will have a better chance for increased frequency of cross links (bonding between neighbouring chains) along their unit length. Consequently, a tendency of improved geometric order should be observed with better chain coherence in the resulting cellulose as compared to situations associated with tracheids characterized by larger microfibril angle. It must be indicated that reasons for this high degree of correlation, as noted above, remain conjectural. Among the structural features studied, microfibril angle was shown to control creep response to the greatest extent. As it increases, total creep increases, the reason being that with a small angle, microfibrils are in a position to bear most of the applied load and therefore their relative movement towards a smaller angle would be less. This results in a small plastic deformation. In the case of a large angle, there is a possibility that the microfibrils have a large tendency to move to a smaller angle causing a large creep response. Wood samples of low specific gravity creep more than those with high specific gravity. This behavior is explained by the higher relative per cent of the S2 layer in the latter. Extractives are shown to contribute significantly to the variation in total creep. They probably act as plasticizers causing a reduction in the primary and secondary bonding between microfibrils. This would facilitate the movement of the stiff inextensible microfibrils to accommodate the creep-inducing stresses. Results obtained in this study were compatible with the proposed hypothesis. / Forestry, Faculty of / Graduate

The hypothesis is examined that, among individual tracheids of coniferous woods, the weights of holocellulose and alpha-cellulose skeletons are a direct quantitative function of their length, independent of species. A total of 28 annual increments, representing wood from nine coniferous genera and seven families, separated into earlywood and latewood fractions, was delignified with peracetic acid and subsequent reduction with NaBH₄. Further reduction to alpha-cellulose followed for a portion of the holocullulose skeletons. About 750 individual holo- and alpha-cellulose tracheid skeletons were measured for length and weight. A specially developed quartz ultra micro-balance, having a weighing range of 0.06 to 14 μg and a precision ± 0.03 μg, was constructed and used to weigh; individual tracheids. Statistical analyses indicated a significant positive curvilinear relationship between length of tracheid and weight of its carbohydrate fraction. Estimated variations accounted for in holocellulose and alpha-cellulose skeleton weights, by the length factor alone were, respectively, 91.9 and 95.7 per cent for pooled data of all the species. No significant differences in holocellulose skeleton weights were evident within species for the same tracheid length, whereas weights of alpha-cellulose skeletons within species, and both the holo- and alpha-cellulose between species, differed significantly. Radial variation for single tracheid weights followed trends similar to those established by others for specific gravity, and percentage of cellulose based on gross wood analyses. Individual tracheids of juvenile wood had significantly lower (1% level) alpha-cellulose skeleton weights than those from mature and overmature wood, while differences were nonsignificant for holocellulose. Overmature wood tracheids were significantly lighter (carbohydrate skeleton weight) than those from mature wood, for the same tracheid length. Differences between earlywood and latewood were explored. For the same tracheid length, both earlywood and latewood tracheids contained similar amounts of alpha-cellulose, whereas the amount of holocellulose per tracheid was higher in latewood. Examination of compression wood also provided positive evidence for the length-weight relationship in tracheids. When weights of compression wood tracheids were compared with those of regular (normal) wood, no significant differences were apparent for holocellulose tracheid skeletons, whereas significant differences were found for alpha-cellulose. It was concluded that, for the same tracheid length, compression wood tracheids may have a lower amount of alpha-cellulose than those from mature (normal) wood, but a higher amount than those from juvenile wood. Changes in Douglas-fir tracheid weights were studied in wood formed before and following tree fertilization. Variations, for the most part, were found to be associated with changes in tracheid length. Qualitative differences attributable to treatment composition (Urea vs. NPK vs. (NH₄)₂SO₄) were also noted, in that some treatments resulted in less weight of alpha-cellulose per unit length of tracheid, when compared with normal wood tracheids. This reduction in cellulose fraction was suggested as a possible factor for differences observed in gross wood specific gravity in wood of some fertilized trees. Results were compatible with the proposed hypothesis. / Forestry, Faculty of / Graduate

No description available.

Thesis (M.S.)--Oregon State University, 1998. / Typescript (photocopy). Includes bibliographical references (leaves 139-143). Also available on the World Wide Web.

No description available.