Thesis (M.A.)--University of Wisconsin, 1936. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 8).

Thesis (Ph. D.) -- University of Tennessee, Knoxville, 2006. / Title from title page screen (viewed on February 6, 2007). Thesis advisor: Timothy G. Rials. Vita. Includes bibliographical references.

Thesis--University of Tennessee. / "ORNL-3328. UC-41--Health and Safety. TID-4500 (17th ed., rev.)." Bibliography: p. 133-138.

Three genera of the Fungi Imperfecti (<u>Alternaria</u>, <u>Cladosporium</u> and <u>Epicoccum</u>) were isolated in high frequency from the pistillate flowers of white oak. These genera occur worldwide and although several species of each genera are parasitic on crop plants, they are primarily saprophytic in the forest ecosystem. Of the three genera, only <u>Cladosporium</u> is parasitic on <u>Q. alba</u>, causing a leaf mold. Several other genera of fungi were isolated in low frequency from the oak flowers. Included in this group were <u>Penicillium</u>, <u>Pestalotia</u>, <u>Curvularia</u>, <u>Pyrenochaeta</u>, <u>Nigrospora</u> and <u>Fusarium</u>. The effect of fungal spores on pollen germination was investigated. Suspensions of pollen grains and fungi spores were cultured in Van Tieghem cells. Pollen germination <u>in vitro</u> was significantly enhanced by <u>Cladosporium</u> and <u>Epicoccum</u>, but unaffected by <u>Alternaria</u>. / Master of Science

No description available.

Dendrochronologists have used the presence of spiral grain as an indicator of old trees for most of the history of the field, although this relationship has been little studied. We examined cross-sections from dead trees and used a 12-mm Haglof Swedish Increment borer to collect cores from living white oak (Quercus alba L.) trees in an Eastern Deciduous Forest stand in southwestern Illinois. Spiral grain is the alignment of wood fibers to the longitudinal axis of trees and is driven by patterns of initial cambial cell division. In this study, we examine environmental factors that may affect spiral grain severity, the usefulness of non-destructive sampling methods (using the 12-mm increment borer), and the relationship between tree age and spiral grain. We tested Brazier’s method (1965) of averaging the spiral grain angle from two radii taken 180 degrees apart (i.e. one diameter in the tree) to get representative grain angles for the whole circumference of a tree at a certain height. The 12-mm increment borer did not produce consistent results in this study; therefore, the collection of cross-sections is advised for the study of spiral grain in white oaks. Brazier’s method should not be used in white oaks and should not be applied universally to all tree species. The severity of spiral grain is expressed in the xylem and may not be expressed in the bark of the tree. Left spiral grain does generally increase in white oaks with age, although this relationship is not always consistent, so a tree without severe spiral grain is not necessarily young.

This study aimed to evaluate the physical and mechanical properties of red oak (Quercus spp.), white oak (Quercus spp.), hard maple (Acer saccharum) and yellow-poplar (Liriodendron tulipifera) and compare them to values from past publications. Mechanical testing was conducted on small, clear, defectree specimens from red oak, white oak, hard maple and yellow-poplar following the standard ASTM D143. Percentage of latewood, moisture content, specific gravity, modulus of elasticity (MOE), modulus of rupture (MOR), compression parallel and perpendicular to the grain and Janka hardness were determined. Results indicated that mechanical properties for red oak, white oak, hard maple and yellow poplar have not changed substantially because the average values remain in a range that is very close to the ones published in past studies. Thus, values from the Wood Handbook can still be used for engineering purposes.

Simulations of tree rings from trees of undisturbed forest sites are used to describe natural, long-term width trends. Ring-width trends of canopy-sized white oak are simulated from regressions of BAI (ring area) data of real trees. Examples are given of a tree from a typical re-growth forest in Illinois and of a more slowly growing tree from an old-growth forest in Kentucky. The long-term width trend was simulated as being toward constant ring width regardless of growth rate of the tree. Conditions by which either increasing or decreasing ring-width trends could be simulated from the same linear BAI trend are examined. I conclude that curvilinear width trends, either increasing or decreasing, represent width adjustments to changes in growth rate (BAI trend) after which the width trend stabilizes to a near-constant value. Interpretation of ring-width trends of trees from undisturbed stands may be useful in assessing stand disturbance history.

Emory oak (Quercus emoryi) and Arizona white oak (Q. arizonica), currently being harvested for fuelwood in encinals of southern Arizona, usually regenerate through stump sprouting. Adjacent to a Huachuca Mountains fuelwood cutting area, 3 replications of four thinning treatments (25%, 50%, 75%, and 100% intensity) were established in January, 1986. Regeneration was assessed one year later by examining the effects of thinning intensity, partial or complete stem cluster cutting, and tree characteristics. Clearcutting greatly increased the proportion of stumps that sprout for Emory oak and increased sprout volume production for both species in comparison to thinned plots. Partially cut multi-stemmed tree clusters were less likely to sprout and have less sprout volume growth after one year than completely cut clusters. Regression models were developed to estimate sprout volume production based on thinning intensity, percent stem basal area cut, tree vigor, number of tree stems, and heart rot.

Although the primary purpose of response function analysis is to identify climate variables that have significant associations with tree radial growth, many researchers are also interested in assessing the strength of these associations. Existing response function programs use a liberal criterion to determine how many climate variables should be included in the analysis. The resulting response function models include a large number of predictor variables. The objective of this analysis is to determine if these response function models are over-fitted to the data used to calibrate them, resulting in over-estimation of strength of associations. PRECON was used to produce response functions for white oak chronologies from n = 149 sites, with separate response functions using 34 monthly climate variables or 10 seasonal climate variables. An analysis of goodness-of-fit statistics for response function calibration provided strong evidence of over-estimation of strength of associations. The degree of over-estimation was greater when 34 monthly climate variables were included in the models compared to models with10 season variables. There was much less evidence of over-fitting for the R-verif statistic that reflects strength of association between predicted and actual tree-ring indices that were not included in model calibration. The PRECON R-verif statistic is the best measure of the strength of multivariate growth-climate associations currently available.