TY - THES T1 - Influence of Water Balance on the Caatinga Stand in the Semi-Arid Interior, Northeast Brazil Y1 - 1990 A1 - Tsuchiya, Akio PB - University of Tsukuba VL - PhD ER - TY - THES T1 - Influence of Gambel Oak on Radial Growth of Southwestn Ponderosa Pine: A Dendrochronological Study T2 - School of Renewable Natural Resources Y1 - 1987 A1 - Biondi, Franco AB -

Gambel oak influence on diameter increment of young-growth ponderosa pines was evaluated by intensively sampling three pine-oak stands on the Beaver Creek Watershed in north-central Arizona. Sampled stands had homogeneous climate, topography, soil parent material, vegetation structure and soil type. Increment cores were collected from five dominant pines on 34 randomly selected study plots. As revealed by dendrochronological techniques, radial growth of sampled pines had fluctuated around a relatively constant level during the last 50 years (1936-85). Differences in this level among stands were related to differences in competition, oak presence, pine age and site index. Pine diameter growth increased with increasing Gambel oak presence and with decreasing intraspecific competition.

JF - School of Renewable Natural Resources PB - University of Arizona VL - MS UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=754449011&sid=5&Fmt=2&clientId=43922&RQT=309&VName=PQD ER - TY - THES T1 - The Implications of Atmospheric Pollen Rain for Fossil Pollen Profiles in the Arid Southwest T2 - Geoscience Y1 - 1986 A1 - O’Rourke, Mary Kay AB - I compared atmospheric and soil pollen values to determine taphonomic influences on pollen in Southwestern soils. Burkard traps sampled atmospheric pollen for six years from multiple sites in Tucson, Arizona. Tauber and soil samples were collected for two years at Tumamoc Hill (Tucson). Morus, Ambrosia, Gramineae, and Chenopodiaceae-Amaranthus characterize Tucson’s airborne pollen. Artemisia, Garrya and summer Pinus pollen are transported from the mountains. Annual pollen capture is similar between Burkard and Tauber samplers. Atmospheric pollen is seasonally variable; annual variability is low. Spatial variability among sites is low. Pollen concentrations vary widely among sites, but taxonomic composition remains constant. Reentrained soil pollen comprises 11% of the airborne pollen. Gramineae and Chenopodiaceae-Amaranthus pollen comprise 90% of the reentrained pollen. Pollen reentrainment varies seasonally. High maximum and minimum temperatures, low dew point and moderate wind speeds are associated with maximum atmospheric pollen concentrations. Winds preceding summer storms cause increased pollen concentrations. Deterioration characterizes pollen from soils. Chenopodiaceae-Amaranthus, Ambrosia, Other Compositae and Graminear are commonly found; Morus is rarely found. Pinus, Sphaeralcea, Boerhaavia and Kallstroemia are present in low numbers. These taxa have thick pollen walls, and they resist destruction. Seasonally collected soil samples have similar pollen spectra. Seasonal airborne pollen variability does not affect the soil pollen spectra. Inoculated soil pollen is well preserved, but pollen is lost rapidly. After one year, pollen concentrations approached background levels for seven of the eight pollen taxa tested. Solidago remained an order of magnitude higher. Pollen morphology may play a role in differential pollen loss. Pollen from the inoculated plots is lost through post-mortem transport. Pollen in soils is time-averaged and exhibits little temporal variability. The average airborne pollen spectra differs from the pollen in the soil. Soil pollen was degraded; inoculated plot pollen was well preserved. I conclude airborne pollen contributes little to the soil pollen of Tumamoc Hill. The soil pollen spectra is affected by selective- or non-deposition of airborne pollen (e.g. Morus), differential pollen destruction, and differential post mortem transport. JF - Geoscience PB - University of Arizona VL - PhD UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=748690901&sid=6&Fmt=2&clientId=43922&RQT=309&VName=PQD ER - TY - THES T1 - The Interpretation of Archaeological Tree-Ring Dates T2 - Anthropology Y1 - 1985 A1 - Ahlstrom, Richard Van Ness AB - A comparative approach to analysis of the body of tree-ring data from prehistoric sites in the American Southwest provides information on patterns of wood use, the effectiveness of interpretive methods, and culture history. Requisite to this approach is an interpretive framework developed since the 1920’s by archaeologists versed in tree-ring analysis. Central to this scheme is indirect dating, by means of which dates derived for biological events of tree growth are applied to progressively more remote events in human history. A new contribution to this framework is an interpretive model that focuses on the shape of tree-ring date distributions. JF - Anthropology PB - University of Arizona VL - PhD UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=752229261&sid=1&Fmt=2&clientId=43922&RQT=309&VName=PQD ER - TY - THES T1 - Inference of past atmospheric delta carbon-13 and atmospheric carbon-dioxide from carbon-13/carbon-12 measurements in tree rings T2 - Geosciences Y1 - 1982 A1 - Leavitt, S. AB -

Carbon dioxide release from fossil-fuel burning is significant enough that we may soon experience perceptible changes in climate with important human consequences. Man's activities involving deforestation and agriculture have undoubtedly also affected atmospheric CO(,2), although quantitative, and even qualitative, net effects of these processes are incompletely understood relative to fossil-fuel production. An accurate reconstruction of past ('13)C/('12)C ratios of atmospheric CO(,2) may provide key constraints on the historical activity of the biosphere as CO(,2) source or sink. Tree rings appear to be a repository of this information but there is much noise in the collection of previous reconstructions, presumably associated with site selection, radial variability, choice of representative wood chemical constituent, and subtle effects of climate on fractionation. This study attempts to avoid these pitfalls and develop a 50-yr (delta)('13)C(,ATM) record from juniper trees (genus Juniperus), in fact, by taking advantage of the influence of climate on fractionation. Trees were harvested from suitable sites in close proximity to weather stations with monthly records of temperature and precipitation. Ring material was then separated from each of the sections in 5-yr intervals from 1930 to 1979 around their full circumference, and cellulose was extracted from the wood. After measuring (delta)('13)C of the cellulose by standard mass-spectrometric techniques, a variety of (delta)('13)C vs. climate functions were examined for each interval. The most useful relationships for at most 7 of the 10 sites were (delta)('13)C with December temperature or precipitation, because the coefficients were nearly constant from one interval to the next (averaging -0.27('o)/oo(DEGREES)C('-1) for temperature and -0.04('o)/oo mm('-1) for precipitation) and the intercepts differed. Local pollution effects are believed responsible for the three anomalous sites. The separation of these regression lines of different intervals is interpreted as the response of the trees to the changing (delta)('13)C of atmospheric CO(,2) so that (delta)('13)C(,ATM) curves are constructed from this spacing. The shape of the best-fit reconstruction suggests the biosphere has acted as CO(,2) source to about 1965 and may now be a net sink. Although these conclusions are limited by certain assumptions and statistical restrictions, evidence from the recent scientific literature tends to support the increasing role of the biosphere as an important carbon sink.

JF - Geosciences PB - University of Arizona VL - PhD UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=752855841&sid=22&Fmt=2&clientId=43922&RQT=309&VName=PQD ER - TY - THES T1 - Investigtions into the Ecological Relationships of Ponderosa Pine in Southeast Arizona T2 - Botany Y1 - 1963 A1 - Dodge, Richard Archie AB - Studies to determine differences between Arizona and ponderosa pine have been carried on in the mountainous areas of southeast Arizona, utilizing plotless phytosociological techniques, morphological studies, and dendrometer investigations. Samples form northern Arizona and Sonora, Mexico, have been included for comparison. Ponderosa and Arizona pine are found in these regions from approximately 7000 to above 9000 feet elevation, associated with oaks in the lower portion of the elevational range and with other conifers in the upper part of the range. Comparison of needle number per fascicle indicated that three-needle ponderosa pine is found at the upper part of the elevational range, while the five-needle Arizona pine occupies habitats below ponderosa pine. Intergradation of the two taxa is indicated by a general increase from three to five needles per fascicle occurring with decreasing elevation; this relationship is more pronounced with decreasing latitude. The number of stomates per unit length of needle was found to increase slightly from north to south. Volume and length of pistillate cones were not useful criteria in separating taxa. Cone density, however, was found to increase with decreasing latitude, and little overlap was present in the two most distant stations. Cone-scale prickle curvature generally tended from an upward to downward pointing direction with decreasing latitude. Dendrometer studies among groups of trees classed as three-needle ponderosa pine, five-needle Arizona pine, and mixed needle hybrids indicated differences in time of radial expansion commencement. The trees classed as Arizona pine and hybrids between Arizona and ponderosa pine commenced radial expansion prior to ponderosa pine. No distinct differences were observed between the two taxa, and it is concluded that Arizona pine is a variety of ponderosa pine. JF - Botany PB - University of Arizona VL - PhD UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=763081241&sid=6&Fmt=1&clientId=43922&RQT=309&VName=PQD ER -