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Thesis (Ph. D.)--University of Idaho, 2005. / Abstract. "December 2005." Includes bibliographical references (leaves 88-92). Also available online in PDF format.

Thesis (I.M.E.S.)--Baylor University, 2009. / Includes bibliographical references (p. 45-48).

In the forest used as range several problems are encountered: (1) accessibility of ranges and (2) invasion of open or lightly timbered ranges by forest growth. For many years stockmen have advocated the use of controlled burning to overcome these problems. However, at present the value of fire for range improvement in this region is not definitely known. Experimental burns have been made to study the effect of fire on vegetation, but little or no work has been done to determine the effect of fire on the soil in such forest range areas. Accordingly, this investigation was initiated in order to determine to what extent soil characteristics in the forest range about Lac Le Jeune have been altered toy forest fires. As a result of forest fires the following changes occurred in the soil of the lodgepole pine, Douglas fir and mixed stands of lodgepole pine, Douglas fir, and spruce forests near Lac Le Jeune. (1) A reduction in percent porosity of the top O-3 inches of soil due to the destruction of both the porous organic horizon and the crumb structure of the upper portion of the B₂ horizon. A further reduction was the result of the soil pores toeing clogged toy ash and suspended soil particles. (2) Increased percentage of capillary pore space of the O-3 inch layer because of the destruction of the larger pores in the Ao horizon and the compaction of the bare soil toy rain. (3) 4 decrease in the percentage of non-capillary pore space or air volume in the O-3 inch layer resulting from the destruction of the Ao with large porese The compacting effect ofrain drops on the crumb structure of the B₂ horizon also aided in decreasing the non-capillary porosity. (4) An increase in volume weight of the O-3 inch layer due to compaction and destruction of the less dense Ao. (5) A decrease in the infiltration rate due to compaction and destruction of soil structure. (6) An increase in soil temperature at a depth of 3 inches resulting from the addition of charcoal which absorbs heat and the destruction of vegetation and forest litter which normally serve as insulating agents. (7) An increase in pH of the Ao and in some cases of the A₂ as a result of the release of basic minerals from the ash, and an Indication that the basic minerals may be leached downwards to the A₂. The pH of the Ao decreased 3 or 4 years after the fire. (8) A decrease in the organic matter content of the duff which had not been totally destroyed by fire. Below the Ao no change occurred. (9) A decrease in the total nitrogen content of the Ao due to volatilization of nitrogen during the fire. No definite trend could be established below the Ao. (10) An increase in total phosphorous in the Ao because of the release of this element from the litter. (11) A reduction in the carbonic acid soluble phosphorous in the Ao due to its combination with the excess calcium to form an insoluble compound. Similarly a decrease in CO₂ soluble phosphorous occurred in the A₂. (12) A decrease in CO₂ soluble potassium in the Ao and A₂ resulting from unrestricted leaching. An Increase in CO₂ soluble potassium in the B₂ horizon. (13) An increase in CO₂ soluble calcium in the Ao of recent burns due to the presence of large amounts of calcium in the ash. Apparently 8 or 9 years are required before ail the added calcium is leached to lower horizons. (14) An increase in CO₂ soluble magnesium in the Ao of the recent burns. The content decreased in the Ao of the older burns because of increased leaching. (15) A decrease in CO₂ soluble nitrates in the Ao. An increase in nitrates in the B₂ is probably a result of increased nitrification at the soil surface followed by considerable leaching. (16) A reduction in the base exchange capacity of the Ao. An increase in exchangeable calcium in the Ao and A₂. An increase in exchangeable magnesium in the Ao, A₂ and B₂ horizons. An increase in exchangeable potassium in the Ao, A₂, B₂, and B₃. An increase in percent base saturation in the Ao, A₂, B₂, and B₃ horizons. / Land and Food Systems, Faculty of / Graduate

Call number: LD2668 .T4 1954 H4 / Master of Science

This research consists of two related yet distinct studies: an observational study of the surface character of the penetration of marine air into the southern Willamette Valley and a climatological study of the summertime air masses of northwestern Oregon. For the observational study, temperature and estimated wind data were gathered by automobile. Mesoscale analysis of several cases indicate that the Marine Air Penetration (MAP) occurs regularly in approximately the same area and is strongly controlled by the topography. Qualitative observation and reasoning strongly suggests that the strong winds and increased stability at the top of the marine layer have an adverse effect upon agricultural field fires. Results of the climatological study indicated that the application of the partial collective method of analysis to July maximum temperature data from the U.S. Climatological Network yielded a meaningful air mass climatology for northwestern Oregon. To our knowledge, this is the first time that the partial collective method has been applied to a region with mountainous areas west of the Rocky Mountains or to the mesoscale. / Graduation date: 1981

Graduation date: 1996

Self-organized spatial patterning of microtopographic features is a trademark characteristic of the Everglades landscape. Anthropogenic modifications to Everglades’ hydrology have reduced and degraded pattern, where ridges occur at higher elevations and spread into open water sloughs under dryer conditions. Wildfire is an important ecological force in the central Everglades and may maintain ridge-slough patterning through reducing ridge size and complexity, and thus preserve habitat heterogeneity. To investigate fire as a patterning mechanism in the central Everglades I examined the shape complexity and area distribution of ridges along a chronosequence of time since fire. Shape complexity did not change following fire, but small and large ridges became more prominent and eventually spread as time since fire increased, suggesting fire may maintain ridge area distribution. Documentation of fires’ effect on ridge size will inform ecosystem and conceptual models detailing the complex interactions that maintain the Everglades ridge-slough patterning. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection