Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references. Also available via the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Abstracted in Dissertation abstracts, v. 16 (1956) no. 2, p. 222-223. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 89-105).

Thesis (M.S.)--Ohio University, June, 2009. / Title from PDF t.p. Includes bibliographical references.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 91-94). Also available via the Internet.

Thesis (M.S.)--West Virginia University, 2010. / Title from document title page. Document formatted into pages; contains vi, 26 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references (p. 25-26).

Thesis (M.S.)--University of Kentucky, 2006. / Title from document title page (viewed on August 22, 2006). Document formatted into pages; contains: vi, 79 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 71-78).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1955. / Typescript. Abstracted in Dissertation abstracts, v. 16 (1956) no. 2, p. 222-223. Vita. Title from title screen (viewed May 9, 2006). Includes bibliographical references (leaves 89-105). Online version of the print original.

In order to gain insights into ultrastructural changes taking place during the conversion of hardwoods into mechanical pulps, refiner pulp fibres were studied in detail using several microscopical techniques. Aspen (Populus tremuloides Michx.) and white birch (Betula papyrifera Marsh.) wood chips were used to produce thermomechanical (TMP), chemithermomechanical (CTMP) and chemimechanical (CMP) pulps. Following the hypothesis that there are fundamental differences in the surface and state of the fibres due to species and processing conditions, four pulps for each species and process were analyzed. Trends in fibre characteristic development were obtained within each group, based on the detailed optical analysis of 300 fibre cross-sections for each pulp. Fibre surface quality was the most important aspect of this study. Retention of middle lamella and of the layer, as well as the extent of exposure of the S₂ layer were evaluated. It was found that TMP processing of wood chips produced fibres with more exposure of the S₂ layer. Chemical pretreatment did not improve the extent of S₂ layer exposure nor the extent of fibrillation. However, the TMP fibres remained stiff, producing pulp sheets of low density and strength. Birch fibres showed a marked tendency to produce separation at or near the S₁/S₂ boundary. This resulted in high exposure of S₂ layers in TMP fibres, but produced a sheath of S₁ and ML around fibres from chemically-treated chips. This sheath was sometimes rolled back, exposing the fibre S₂ layer. Aspen TMP pulps showed high proportions of fibres with partially exposed S₂ layer. The application of chemical pretreatments to aspen chips resulted in fibres of similar levels of S₂ exposure than those achieved by TMP processing of this species, but only after reaching freeness levels of about 100 mL CSF. Fibres that showed radial failure were frequent in TMP but not in CTMP nor CMP pulps. The breakdown pattern of tension wood fibres (G-fibres) was also studied. TMP processing showed preferential breakdown of G-fibres, from which the G-layers were freed. This was not the case in the G-fibres from chemically-treated chips, in which the G-layer generally remained inside the fibres. Other categories discussed in the analysis of fibre cross sections included fibres with delamination of the S₂ layer and proportion of fibres distorted due to chemical impregnation. The breakdown of vessel elements (VE) was studied by comparing VE size frequency distributions and the proportion of whole VE that survived refining. TMP reduced VE into small fragments showing virtually no whole VE, while wood softening due to chemical pretreatment was responsible for a high proportion of whole VE in CTMP and CMP pulps. The VE from birch tend to be destroyed more easily than those from aspen, due to the intervessel pitting arrangement of the former. It is concluded that despite superior bonding potential of TMP fibres due to: - large S₂ exposure in fibres on account of separation at or near the S₁/S₂ boundary, - increased fibrillation, - longer fibrils in fines, and - release and exposure of highly cellulosic G-layers from tension wood in the case of aspen, the lack of conformability of TMP fibres, which translates into low sheet density, negates the promising benefits that otherwise would be obtained. / Forestry, Faculty of / Graduate

The feasibility of utilizing the aspen, birch and cottonwood stands which are found in large volumes in northeastern British Columbia was investigated. The study included raw material analysis, plant design of five integrated production lines, market study and model of investment. The integrated complex was designed to produce aspen and cottonwood dried veneer with an annual capacity of 70 000 m³, 3 mm thick, 13 500 m³/year of sliced - dried birch face veneer, 0.8 mm thick, 40 billion splints for match manufacture, 10 000t of pelle- tized aspen bark and 50 GJh of thermal energy. The aspen, cottonwood and birch veneer production was chosen because of its higher profitability than other products and its market potentials. The residue utilizing lines were included to add manufacturing values in addition to the main products. The complex is expected to consume 140 000 m³ of aspen and cottonwood and 30 000 m³ of white birch yearly. This volume is considered a fraction of the species annual allowable cut in the Fort Nelson Forest Unit. A total capital investment of $29 373 000 is required; of which $17 083 000 would be for fixed investment and $12 290 000 for annual operating cost. The expected after tax profit on investment would be $10 910 000/year, based on annual sales of $3k million. Projected annual return on investment is expected to reach 6k% of the fixed investment with a payout of 1.6 years. Sixty eight tables and 1+9 figures in addition to plant layout for the entire integrated industrial complex are included in the study as illustrating material. / Forestry, Faculty of / Graduate

Surface mining for coal in the Appalachian region has removed over 0.6 million Ha of mixed mesophytic forest. Successful reforestation would be beneficial, but questions remain concerning application of reclamation and reforestation methods on operational scales. Four experiments were performed testing these methods on newly reclaimed and previously reclaimed, but unused, former mines. On newly reclaimed sites, loose grading during reclamation reduced erosion and increased plant community diversity compared to smooth grading. Seeding only annual ryegrass (Lolium multiflorum) for erosion control, along with tree planting, increased plant community diversity and improved survival and growth of hybrid American chestnut (Castanea dentata x Castanea mollissima), compared to conventional seeding. Surface water infiltration was positively correlated with herbaceous ground cover. On older mines, subsoil ripping to alleviate compaction improved tree survival and growth, in some cases, after five growing seasons. Of the three species groups planted, including Eastern white pine (Pinus strobus), mixed native hardwoods had the best survival and hybrid poplar (Populus deltoides x Populus trichocarpa) produced the most biomass. Hybrid American chestnuts survived and grew better when planted as bare-root seedlings than when planted as ungerminated nuts in tree tubes, demonstrating the potential for planting bare-root chestnut seedlings along with other species when reforesting reclaimed surface mines. This can aid in restoring American chestnut, functionally extinct since the blight (Cryphonectria parasitica), to its former range. These cultural practices can be employed to accelerate reforestation of mined lands, but many questions remain about their capability to fully restore ecosystem structure and processes. / Master of Science