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Thesis (M.S.)--Oregon State University, 1984. / Typescript (photocopy). Includes bibliographical references (leaves 38-41). Also available on the World Wide Web.

Thesis (Ph. D.)--John Hopkins University, 1930. / Cover title. Reprinted from Ecological monographs, vol. 1, no. 1, January, 1931. Running title: Water relations of seedling conifers. "Literature cited": p. 96-98.

Thesis (Ph. D.)--John Hopkins University, 1930. / Cover title. Reprinted from Ecological monographs, vol. 1, no. 1, January, 1931. Running title: Water relations of seedling conifers. "Literature cited": p. 96-98.

Thesis (M.S.)--Humboldt State University, 2006. / Includes bibliographical references (leaves 67-72). Also available via Humboldt Digital Scholar.

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The present research aims to establish the depth of abiotic and invertebrate edge-effects occurring in plantations of two conifer species, and the resulting effects of management practices on 'edge' and 'core' invertebrate communities. Near complete invertebrate samples were collected using chemical knockdown allowing analysis of invertebrates at the order, family, genus, species and guild level. Similar invertebrate densities per m[2] ground area occurred in both tree species, although communities differed between them, Pinus sylvestris supporting a more diverse community than Picea sitchensis. Species richness, diversity and densities varied with distance from plantation edge with the Acarina, Araneae, Coleoptera, Collembola, Diptera and Hemiptera showing particularly strong responses to edge proximity. Abiotic edge-effects, although variable between transects, occurred to an average depth of 30 metres with an approximate 1 C drop in temperature and a 5% increase in relative humidity towards the core. Invertebrate edge-effect depths varied with species, ranging from 5 to 80 metres. In P. sitchensis invertebrate richness and densities, particularly for Coleoptera, Araneae and Hemiptera were higher in the edge habitat, whilst increased richness and diversity occurred in the core of P. sylvestris. Edge habitat is key to optimising richness in P. sitchensis, however application of core-area models shows that current plantation management fails to maximise edge habitat. Reduction of patch size and/or increasing edge features will increase species richness. In contrast core habitat is vital to species richness in P. sylvestris. Current small patch size limits invertebrate richness, increased patch size and implementation of edge buffer zones would protect core habitat thus enhancing invertebrate species richness.

Lack of a selective holocellulose isolation procedure and the problem of limited material have long frustrated the attempts of wood scientists to accurately measure and describe carbohydrate yields within coniferous growth zones. A new method has been devised for micro-cellulose determination, Alpha-(formula omitted) cellulose yield maybe quantitatively estimated as the corrected yield of nitrated wood meal. Three - O.1 g wood meal samples provide a statistically reliable determination. A major limitation of the new technique, however, is that it cannot be applied to all woods. Sixty positions within ten increments representing five Canadian coniferous woods of different genera were examined and intra-incremental patterns were constructed. Anova and Duncan's test showed latewood (formula omitted) -cellulose yield to be greater than that of earlywood by a highly significant degree. Alpha-cellulose content throughout mature growth zones was estimated reliably by linear correlation or, more accurately, by logarithmic transformation used in a recent mathematical model. The successful application of the latter is its first reported use describing the non-linear behaviour of a wood chemical property across a coniferous increment. These patterns showed relationship of the long-chain carbohydrate fraction to seasonal development within coniferous growth zones. In addition, six of the ten patterns demonstrated new chemical evidence pertaining to a physiologically significant phenomenon in earlywood. Therein, minimum (formula omitted) -cellulose yield occurs at considerable cellular depth following cambial reactivation in the growing season. First-formed earlywood appears to retain some similarity at the chemical level of organization to last-formed tissues of the preceding season. Later-formed earlywood (i. e. , from the present year) does not appear to retain such similarity. From earlier work of this laboratory, lignification patterns were described for the same materials, using ultraviolet measurements on acetyl bromide-acetic acid digestion products of two wood meal samples. Examination of (formula omitted) -cellulose and lignification patterns provided evidence for their mutually exclusive behaviour. For the ten increments studied, the (formula omitted) -cellulose estimate (x̅ = 45.9 + 2.0%) was the exact complement of lignification (x̅ = 27. 4±1. 9%) at all positions but one. The linear regression for data from all increments was highly significant ( r = - 0.785). In addition, micro (formula omitted) -cellulose and micro lignin values, when combined, showed a definite tendency to cluster about a central value (x̅ = 73. 4 ± 1. 2%) suggesting that certain species require a common, critical measure of high molecular weight material. Dispersion about combined lignin and (formula omitted) -cellulose estimates was significantly less than about either of their individual means. This suggests much closer physiological control over the combination of these chemical entities, indicating that tree physiology is oriented more towards the finished bio synthetic product than towards the individual components involved in such a system. As a means of measuring successful nitrocellulose preparation, intrinsic viscosity (formula omitted) was used to indicate presence or absence of extensive degradation. Because of the highly variable at each position tested, no consistent trends in chain length were found across growth zones. However, in four increments, significant differences in (formula omitted) throughout the earlywood provided further evidence of two earlywood types. / Forestry, Faculty of / Graduate

Water availability for uptake by tree seedlings is determined both by the soil water potential in relation to seedling needle water potential and by the resistance to flow of water through the soil, root and stem, to the needles. This study was designed to focus principally on water uptake resistances. The effects of soil texture and tree species on this water uptake resistance were quantified through the use of an Ohm's Law model suited to water flow through the soil-plant system. The study was conducted on one-year-old potted seedlings in a controlled environment growth chamber. Needle water potential (ΨN) of Douglas-fir is not much affected by soil water potential (Ψs) down to about -2.5 MPa, where the calculated water uptake rate becomes very small. However, soil texture does significantly affect the resistance to flow into the seedling and thus affects the water uptake rate by the seedling. The total resistance to water uptake increases as the soil dries. Coarser textured soils show consistently higher water uptake resistances over the soil water potential range -0.5 to -2.5 MPa. It is inferred that differences in resistance are associated with unsaturated, hydraulic conductivity characteristics of the soil and soil-root contact. Unlike Douglas-fir, both western and mountain hemlock show a large decrease in needle water potential as the soil dries down to a Ψs of about -3.0 MPa. The water potential difference (Ψs - ΨN) for hemlocks is less where Ψs is higher than -1.8 MPa, and greater where Ψs is less than -1.8 MPa, than (Ψs - ΨN ) for Douglas-fir in these s s N experiments. Despite these differences, the resistance to water uptake for both hemlock species is much greater over the soil water potential range -0.5 to -2.5 MPa, and thus the water uptake rates are much less than for Douglas-fir with the same soil, even though root densities and root surface areas are much larger for the hemlocks. This behavior is most pronounced with mountain hemlock. These differences are thought to be related to higher tissue and (perhaps) soil-root contact resistances in the hemlock species. The soil resistance appears to be small, at least down to Ψs of about -2.0 MPa, in these experiments. However, root densities are probably much greater than one might expect in the field. / Forestry, Faculty of / Graduate

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