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Thesis (M.S.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 93-97). Also available on the World Wide Web.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 147-160). Also available via the Internet.

Thesis--Oregon State University. / Includes bibliographical references (leaves 115-135). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1957. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 95-114).

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 209-226). Also available on the World Wide Web.

The effect of two commercial fertilizers on some wood properties of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) has been determined at macro- and micro- levels. Three trees, approximately 30 years of age, representing two treatments, (NH₄)₂SO₄ and NPK (N-NO₃), and an untreated control, were available. Selected trees had been fertilized first in the year 1957 at 21 to 23 years of age, and subsequently in the year 1959, with 400 lb of fertilizer per acre each time. Sections from five vertical levels of each tree were examined. The wood investigated represented each growth increment formed after 1956 and some selected ones before 1956. Response to treatment was found in the year following fertilization, with an accelerated growth rate, and a general decrease in specific gravity, per cent latewood and mean tracheid length. Maximum growth response occurred the year of re-fertilization or the year following. The greatest reduction of per cent latewood and specific gravity accompanied re-fertilization. For both fertilizers, a 4.4 per cent reduction in specific gravity followed the two separate applications, but differences in specific gravity before and after treatment were not statistically significant. Tracheid length reduction subsequent to NPK treatment was 14.5 per cent compared to less than one per cent with (NH₄)₂SO₄, but again the differences before and after treatment were not statistically significant. The tree with initially longer tracheids responded more adversely than that with shorter tracheids. Relationships between several wood characteristics indicated that macro-specific gravity was highly influenced by per cent latewood, diameter at breast height and increment width. These three variables together accounted for 57.6 per cent of the total variability in specific gravity. Macro-specific gravity was highest at the base and lowest at the top of the tree, and at any one height it was lower near the pith and higher towards the bark. Six consecutive growth increments, representing three age segments (before treatment, including and after first and second treatments, respectively), were studied at micro-level from breast height sections of each tree. Six positions within each increment were examined. Results indicated a 20 per cent reduction in tensile strength due to NPK treatment that was highly significant statistically. No apparent influence was found for (NH₄)₂SO₄; tensile strength values were, however, lower following re-fertilization as compared to untreated control. Micro-specific gravity and tracheid length followed trends similar to those of tensile strength. Strong correlation (r=0.92) was observed between micro-specific gravity and micro-tensile strength. It is proposed that N in the form of (NH₄)₂SO₄, when compared to NPK, was a better fertilizer for the two treated trees examined. It was concluded that weak residual effects of fertilization on these Douglas fir trees persisted four to five years after re-fertilization. For both treatments, increased specific gravity and growth rate resulted whereas cell length failed to demonstrate normal increase with age. / Forestry, Faculty of / Graduate

The potential for using RMP (refiner mechanical process) pulp mill fibre waste as a soil amendment was investigated by determining levels of net carbon mineralization. Under optimum conditions (laboratory incubation study), the pulp fibre waste, being a relatively homogeneous substrate, was found to mineralize at one rate of -0.0078 d⁻¹. In field applications the rate of net mineralization was slower, with rates of -0.0034 d⁻¹ and -0.0037 d⁻¹, as determined by soil respiration and litter bag trials, respectively. A loading effect was noted for this amendment, where increasing the levels of application was found to cause decreases in the mineralization rate. Using pulp fibre waste in forest landing rehabilitation appears to increase the levels of microbial activity in the surface horizon. The higher levels of productivity should lead to improvements in soil structure, and would be a better alternative to only tilling and fertilizing the soil. / Land and Food Systems, Faculty of / Graduate

The objective of this study was to examine the relationships between Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) foliar nutrient status and forest floor chemical properties. Foliar nutrient analysis data were collected on 27, 50- to 140-year-old Douglas-fir stands, for which the forest floor chemical properties had previously been analysed. The 27 sites encompassed a broad geographical area within the Coastal Western Hemlock Biogeoclimatic Zone. Foliar samples were individually analysed for total S, N, P, K, Ca, Mg, B, Cu, Zn, Fe, Al, Mn and for AFe (active iron). Four foliar nutrient ratios (N/S, N/P, K/Ca, Ca/Mg) were additionally calculated. As the foliar sampling intensity was often below that recommended in the provincial sampling guidelines, the precision of the within-site foliar nutrient variable mean values was examined for the lowest sampling intensity used in this study (n=8). Foliar nutrient and ratio variances from 6 of the 27 sites, for which 15 trees per site had been sampled, were used as population variance estimates. A sampling intensity of n=8 was found to be sufficiently large to provide foliar nutrient variable mean estimates with an allowable error of 20% (∝ =0.5) for all but the following foliar nutrients and ratios: B, Cu, Ca/Mg and K/Ca. Two combinations of forest floor horizons were examined for possible relationships with foliar nutrient variables: L plus F and L plus F plus H. These two combinations of forest floor horizons were referred to as the LF and the LFH layers. The two criteria used to select forest floor chemical properties are as follows: (1) the precision of the forest floor chemical property site estimate was less than or equal to 20% (∝=0.5) for the field sampling intensity used, or (2) the forest floor chemical property was an established measure of nutrient availabilty. The 12 LF and 16 LFH chemical properties selected included: LF and LFH: pH (CaCl₂), total-S, -N, -P, -Cu, -Zn, -Mg, -K, -C, Min-N (anaerobic mineralizable N), KC1-N (KC1 extractable N, A (lipids), and LFH (only): exK, exCa, exMg (1M NH₄OAC exchangeable bases) and extP (Bray P₁ extractable P). Simple linear relationships between foliar nutrient variables and LF and LFH chemical properties were initially examined. Strong negative associations were found between foliar S and certain forest floor chemical properties, namely LF: pH, LMg and LFH: pH, LMg, LexMg, LexCa, LexK (here and following, L signifies the natural logarithm). It was hypothesized that these relationships reflected the effect of the different sources of plant available sulphur predominant on the higher (17 sites) and lower (10 sites) forest floor pH sites. Organic sulphur mineralization and mineral weathering were suggested as the major sources of plant available sulphur for the higher forest floor pH sites; anthropogenic atmospheric sulphur was suggested as the major source of plant available sulphur for the lower forest floor pH sites. The efficacy of forest floor (LF and LFH) chemical properties for predicting and classifying foliar nutrient status was examined through the use of multiple regression and discriminant analysis, respectively. These analyses were performed for the four foliar nutrient variables for which a range in sufficiency and possible deficiency (actual or inducible) was indicated for the stands sampled: foliar N, S, AFe and N/S. One regression model of potential predictive value was found for foliar LS. Together, LFH pH and LFH LCu statistically accounted for 79% of the observed variation in foliar LS. Several LF and LFH chemical properties were able to reliably classify stands into the following total foliar S groupings: sufficient and deficient (actual or inducible). LF LMg and LF A provided the best classification of stands into the groupings: S sufficiency and N-inducible S deficiency, as defined by foliar N/S. Three LFH chemical properties: P, S, and LexK provided the best classification of stands in terms of adequate and slight to severely deficient foliar N status. LF and LFH chemical properties were only poorly able to classify foliar AFe status. It was concluded that the relationships found in this study could not be extrapolated beyond the present study, due to the unforeseen, yet probable, influence of slightly acidic precipitation on both nutrient cycling and foliar nutrient status for 10 of the 27 stands examined. / Land and Food Systems, Faculty of / Graduate

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