No description available.

The objectives were to induce and study the effects of adverse climatic conditions on sugar maple. Two different snow removal treatments were applied over the winter period of 1990-91 and a tarpaulin treatment was applied over the summer period of 1991 to a sugar maple stand in the Morgan Arboretum. The complete snow removal and tarpaulin treated trees showed decreased leaf water potential and increased peroxidase activity over the growing season. Foliar Ca was reduced in the two different snow removal treatments early in the growing season while foliar N was reduced in the complete snow removal trees late in the growing season. Soil NO$ sb3 sp-,$ K$ sp+$ and Mn$ sp{2+}$ was elevated in the complete and partial snow removal, and tarpaulin treatments at various times throughout the growing season. The snow removal treatments affected both water and nutrient status as well as tree health.

No description available.

No description available.

Many variety computer systems for advanced mathematics are now being used by hundreds of thousands of engineers, scientists and students across a broad range of exact science disciplines to perform calculations, drawing, to interface with other programs, and to publish their “live” documents on the Web. Maple, Mathcad and Matlab are computer systems for advanced mathematics and a rich problem-solving environments that gives you a wide choice of tools and supports a variety of analysis and visualization techniques. They provide many ways of representing data and mathematical expressions graphically using plots. They also have unique animating of graphs. Animation feature allows you to see a plot change in real time when the value of a variable changes. In this paper, we investigated and compared the creating, controling and using animation in Maple, Mathcad and Matlab and give animation examples for teaching mathematics. The main stress of this research work was to clear and to explain ways for practical use of animation as this area of computer systems has not been investigated in Lithuania yet.

Under field conditions, vesicles were the most frequently observed mycorrhizal structures in sugar maple, while greenhouse grown seedlings formed more arbuscules. Seasonal fluctuations of vesicular-arbuscular mycorrhizae existed. Mycorrhizal associations formed within 30 days in the greenhouse. Arbuscules were usually formed from hyphal coils and occasionally from linear hyphae spreading from cell to cell. Degenerating arbuscules were not observed. The addition of basic cations increased the number of vesicles formed and decreased the overall infection rates and seedling growth. The uptake of calcium, magnesium, and nitrogen decreased, and potassium uptake increased as fertilization rates increased. Positive correlations existed between the incidence of arbuscules and plant growth and health and between the incidence of arbuscules and the uptake of calcium, magnesium, nitrogen and phosphorus, and with the uptake ratios and these elements with potassium. This suggests that vesicular-arbuscular mycorrhizae may in some way be regulating ionic balance in these seedlings.

Sugar maple foliage litters from fertilized and unfertilized plots on a base-poor site and from a naturally base-rich site were incubated in litterbags of 1 and 3 mm mesh on fertilized and unfertilized plots at the base-poor site. Mass loss of unfertilized litter was slower in fertilized than unfertilized plots, suggesting a negative effect of fertilization on decomposers. Mass loss of fertilized litter was faster than unfertilized litter in the same plots, indicating that changes in litter quality due to fertilization enhanced microbial decomposition. Mass loss was higher in large mesh than in small mesh size bags, suggesting that larger soil fauna played a significant role in litter decomposition. / Potassium appeared to be rapidly leached, whereas Ca and Mg were released at rates more closely related to litter mass loss. Nitrogen was mineralized from N-rich Arboretum litter only; all other litters immobilized N. Release of Ca and Mg was reduced significantly on fertilized plots. Large soil fauna enhanced Ca release, while they delayed N-mineralization in Arboretum litter.

Thesis (Ph. D.)--University of Wisconsin--Madison, 2004. / Includes bibliographical references (p. 335-353). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. Includes bibliographical references.

Thesis (M.A.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. [45]-48.