@mastersthesis {911, title = {Restoring Ponderosa Pine Forests in the Black Hills, South Dakota}, volume = {Master of Science}, year = {2001}, pages = {50}, school = {University of Arizona}, address = {Tucson}, abstract = {

Ponderosa pine (Pinus ponderosa Laws.) forests have changed considerably during the past century, partly because recurrent fires have been absent for a century or more. In dense stands of ponderosa pine in the Black Hills of South Dakota, a layer of pine needles has replaced inderstory vegetation. I examined the disturbance history, soil seed bank, and effects of prescribed burning and overstory reduction on understory vegetation in a ponderosa pine stand in the northern Black Hills. Cessation of fires, prolific ponderosa pine regeneration, and logging led to a dense, even-aged stand with very little understory vegetation and few viable seeds in the soil seed bank. Understory vegetation did not respond to the restoration treatments the first growing season, but did respond the second growing season. Paucity of viable seeds in the soil seed bank does not appear to constrain recruitment of understory vegetation in dense ponderosa pine forests of South Dakota.

}, keywords = {black hills, fire history, overstory, pinus ponderosa, ponderosa pine, prescribed fire, restoring, soil seed bank, south dakota, stand age, understory}, author = {Wienk, Cody Lee} } @mastersthesis {830, title = {A Dendrochronological Record of Pandora Moth (Coloradia Pandora, Blake) Outbreaks in Central Oregon}, volume = {MS}, year = {1997}, pages = {159}, school = {University of Arizona}, address = {Tucson}, abstract = {Pandora moth (Coloradia Pandora Blake) is a phytophagous insect, defoliating ponderosa pine trees in the western United States. However, long-term studies of this insect and its effects on the forest ecosystem have not been conducted. Using dendrochronological techniques, I examined past timing and intensity of defoliation through its effects on radial growth of trees in the forests of south central Oregon. Pandora moth leaves a distinctive ring-width "signature" that was easily identifiable in the wood. The growth for the first year of the signature was half the normal ring-width with narrow latewood. The following two years produced extremely narrow rings, with the entire suppression lasting from 4 to 18 years. Twenty-two individual outbreaks were reconstructed from this 620 year chronology. I found that pandora moth outbreaks were episodic in individual sites, with a return interval of 9 to 156 years. Conversely, on the regional scale of south central Oregon, outbreaks demonstrated a 37-year periodicity. On average, pandora moth defoliation caused a 29\% mean periodic growth reduction in defoliated ponderosa pine trees. Spread maps of the first year that sites demonstrated suppression were plotted revealing an apparent annual spread of the outbreaks. Examination of a fire history on one pandora moth outbreak site suggested that pandora moth outbreaks delay fire by interrupting the needle fall needed for fire spread. Superposed epoch analysis showed that the year that the outbreak was first recorded was significantly dry and the fourth year prior was significantly wet. Therefore, climate may be a triggering factor in pandora moth outbreaks. The stem analysis demonstrated that the percent volume reduction was the greatest at the base of the tree and declined further up the bole. The percent volume reduction in the canopy of the trees was variable with outlying high and low values. THe mean volume reduction per outbreak was .053 m3 per tree. Although this insect is considered a forest pest and causes inconvenience for people living nearby, pandora moth is not as widespread and damaging as some other phytophagous insects. However, its very distinctive ring-width signature and the length of the ponderosa pine record enables reconstruction of very long outbreak histories, which may deepen our understanding of the interaction between defoliating insects and their ecosystem. }, keywords = {Coloradia pandora, dendrochronology, entomology, fire, fire history, growth, insect, Oregon, outbreak, pandora moth, phytophagous, ponderosa pine, ring-width, tree ring}, author = {Speer, James Hardy} } @mastersthesis {907, title = {Holzanatomische Untersuchungen zur Rekonstruktion der Feuergeschichte eines Bestandes von Pinus ponderosa Laws. in den Santa Rita Mountains, Arizona}, year = {1992}, note = {

Please contact the Laboratory of Tree Ring Research to view this collection.

}, month = {05/1992}, school = {Universitat Freiburg}, keywords = {Arizona, german, ponderosa pine, santa rita, santa rita mountains}, author = {Wolfgang Ortloff} } @mastersthesis {906, title = {Potential for Use of Cottonwoods in Dendrogeomorphology and Paleohydrology}, volume = {Master of Science}, year = {1987}, pages = {52}, school = {University of Arizona}, address = {Tucson}, abstract = {

Fremont cottonwoods contain valuable environmental information that can be used to augment knowledge of fluvial systems. Cottonwoods have not been commonly used in dendrochronological studies because of difficulty in determining ring boundaries, uncertainty if growth rings are annual, as well as doubt whether riparian species cross-date. A new method of sample examination utilizing transmitted light permits clear view of ring boundaries, and resampling techniques suggest that the growth rings are annual. The cottonwoods studied are growing along Twentyfive Mile Wash and Harris Wash, both tributaries of the Escalante River in south-central Utah. Cross-dating was found among most of the cottonwood cores, except those from Harris Wash, which were approximately dated by ring counts. After application of rigorous dendrochronological methods, ring counts were deemed to be sufficient to estimate ages of cottonwoods, as the cores contain no missing rings and few false rings. Careful ring counts would accurately estimate the age of these trees to within 1 to 2\%. The cottonwoods studied are partially buried by 2 to 4 m of terrace sediments. Dating of the trees provides a minimum age for the terraces of 130 to 227 years. Lack of cross-dating between the cottonwoods and nearby arid-site ponderosa pines indicates that these species respond to different environmental or climatic factors. The ponderosas are limited by lack of moisture, while correlation analysis suggests that the cottonwoods are limited by excess moisture. Soil saturation often causes a decrease in growth due to insufficient oxygen available to the roots. However, in years with very little precipitation, cottonwood growth appears to be limited by lack of moisture, and in these particular years a small ring occurs in the cottonwood series as well as in the ponderosa series. Growth suppressions in the cottonwoods correlate either with known floods on the Escalante or Paria Rivers, or with droughts. If the suppression is due to drought, a corresponding small ring occurs in the ponderosas. Timing of paleofloods can be interfered from suppressions in the early portion of the cottonwood chronology. Rates of alleviation were estimated at 0.9 to 3.0 cm/yr by dividing the amount of sediment above the basal root flare of the trees by the age of the trees. All of these methods would be especially useful in dendrogeomorphological studies on ungaged watersheds, before periods of record, or in watersheds where cottonwoods are the only tree species available.

}, keywords = {cottonwood, dendrochronology, dendrogeomorphology, escalante, fluvial system, fremont, harris wash, paleoflood, paleohydrology, paria, ponderosa pine, terrace sediment, tree ring, twenty five mile wash, utah}, author = {Clark, Susanmarie} } @mastersthesis {571, title = {The Effects of Fire Exclusion on Growth in Mature Ponderosa Pine in Northern Arizona}, volume = {Master of Science}, year = {1983}, pages = {28}, school = {University of Arizona}, address = {Tucson}, abstract = {

Dendrochronological techniques were used to assess the effect of fire exclusion on the radial growth of two age classes (approximately 150 to 300 years old) of mature ponderosa pine. Decline in average radial growth in both classes is coincidental with the establishment of a large ponderosa pine seedling crop in 1919 that has since become an extensive stand of stagnant, overcrowded saplings.

F and t tests of tree ring indices comparing the time period before and after 1920 show that growth has significantly declined since 1920 in both age classes. F and t tests comparing the two age classes suggest that growth was similar before 1920, but the older age class shows a significantly stronger growth decline than the younger age class. Spearman Rank Correlation tests indicate that in both groups there was no trend or a tend toward increasing tree ring indices before 1920 in both age classes, but that after 1920 there was a strong, significant trend toward decreasing tree ring indices in both groups, and that the trend is stronger in the older age class. These results suggest that the older trees are experiencing a more pronounced growth suppression effect than the younger trees.

October and July Palmer Drought Severity Indices from 1931 to 1976 were tested for trend toward drought using the Spearman Rank Correlation. There was no trend toward drought during these months, which have the most significant climatic relationship to ponderosa pine growth in northern Arizona. Therefore the growth decline at Chimney Spring may not be attributed to climate.

No environmental factor has changed at Chimney Spring, other than fire exclusion and subsequent seedling establishment. Competition for soil moisture and nutrients, reduced nutrient cycling and soil moisture losses from litter interception may all be factors contributing to the growth decline in the mature ponderosa pines at Chimney Spring.

Key words: age classes, competition, dendrochronology, \“dog-hair\” thickets, fire exclusion, forest, northern Arizona, Pinus ponderosa, radial growth

10-year index:

}, keywords = {age classes, chimney spring, competition, dendrochronology, dog hair thickets, fire, fire exclusion, forest, mature, northern arizona, palmer drought severity indices, pinus ponderosa, ponderosa pine, radial growth, spearman rank correlation}, author = {Sutherland, Elaine Kennedy} } @mastersthesis {573, title = {Fire History of the Gila Wilderness, New Mexico}, volume = {Master of Science}, year = {1983}, pages = {156}, school = {University of Arizona}, address = {Tucson}, abstract = {

A data base of fire occurrence was established for the Gila Wilderness by analyzing fire scars and compiling fire records. Cross sections of 44 fire scarred ponderosa pine trees (Pinus ponderosa Laws.) were collected from three study areas. Crossdating of more than 800 individual fire scars revealed that extensive surface fires were a common occurrence prior to 1900. Mean fire intervals for a 250-year period prior to 1900 were approximately four to eight years and fire intervals ranged from one to 26 years. Intensive grazing and fire suppression efforts after 1900 resulted in a sudden decrease in number of fires recorded by the sample trees.

A 72-year record (1909-1980) of fire occurrence in the Gila National Forest was compiled from Forest Service records. The fire records and fire scar evidence suggest a need for continued emphasis on fuels reduction and greater flexibility in the Prescribed Natural Fire program.

}, keywords = {crossdate, dendrochronology, fire, fire history, fire scar, gila national forest, gila wilderness, new mexico, pinus ponderosa, ponderosa pine, tree ring}, author = {Swetnam, T.} }