Now showing items 14193-14212 of 14977

    • Tree characteristics in relation to growth of ponderosa pine

      Whiting, Robert Montague (The University of Arizona., 1965)
    • Tree growth and understory production after thinning ponderosa pine in Arizona

      Beets, Martin Levi, 1943- (The University of Arizona., 1971)
    • A tree ring analysis of four tree species growing in southeastern New York state

      Cook, Edward Roger, 1948- (The University of Arizona., 1976)
    • Tree Rings In Velvet Mesquite (Prosopis velutina Woot.): An Exploratory Study of Wood Anatomy, Crossdating, Climate-Growth Relationships, Life History, and Above-Ground Biomass

      Trouet, Valerie; Shepard, Robert Michal; Trouet, Valerie; Archer, Steve; Scott, Russ; Sheppard, Paul (The University of Arizona., 2015)
      Velvet mesquite (Prosopis velutina Woot.) is a common tree in semi-arid, southwestern U.S. savanna ecosystems. While there are studies that examine some of the physiological and ecological aspects of this tree (response to fire, net ecosystem exchange, encroachment into grasslands, yearly growth through dendrometer bands, among others), the wood anatomical features of a growth ring, suitability for dendrochronological research, life history, and above-ground biomass through time are knowledge gaps that can be filled. The purpose of this study was to examine these gaps in order to better understand the role of velvet mesquite in these ecosystems. Wood anatomical analysis showed that velvet mesquite has a semi-ring porous structure and termination of the growth ring is indicated by a small band of parenchyma. Visual crossdating of velvet mesquite was successful but a complex growth habit, with both eccentric and lobate growth, combined with ecological pressures hampered statistical validation of the chronology. Seasonal climate-growth analysis of dated rings showed a strong positive correlation to previous year September and October precipitation and a strong positive partial correlation to previous year September and August mean temperature. Life history through growth curve analysis showed no age related growth trend (either s-shaped or log normal) indicating the maximum age of velvet mesquite stems sampled (130 years old) can become much older with many releases and few suppressions. Above-ground biomass of these trees are low compared to higher elevation forest biomass, but similar to other savanna ecosystems of the southwest. The use of velvet mesquite in dendrochronological research would greatly benefit from a complete analysis of wood anatomy, and addition of more samples from various locations to verify dates and begin building more reliable chronologies for this species across its range. These additions would allow for a greater understanding of stand and tree level responses through suppressions and releases, and understand the biomass accumulated above-ground through time.
    • Tree-ring reconstruction of western spruce budworm outbreaks in the Rio Grande National Forest, Colorado

      Swetnam, Thomas W.; Ryerson, Daniel Eric (The University of Arizona., 1999)
      Tree-ring records were used to reconstruct the spatial and temporal patterns of western spruce budworm (Choristoneura occidentalis Freeman) outbreaks in the Rio Grande National Forest (RGNF) of southern Colorado. Reconstructions at 11 host stands showed a synchronous pattern of outbreaks with a peak in the number of trees recording outbreaks over the entire RGNF on average every 24 years. These synchronous periods of outbreaks coincided with periods of increased moisture as indicated by an independently reconstructed summer Palmer Drought Severity Index, while relatively few trees recorded outbreaks during dry periods. The reconstruction on the RGNF does not support the hypothesis that human land use has significantly altered outbreak patterns. Tree response to outbreaks in the RGNF was different from prior studies as reductions in growth were typically detectable only when growth was compared to that of nonhost tree species.

      Armstrong, Glenn Irons. (The University of Arizona., 1984)

      Smadi, Mithkal Moh'd (The University of Arizona., 1986)
    • Trends in grassland bird abundance following prescribed burning in southern Arizona

      DeStefano, Stephen; Mannan, R. William; Kirkpatrick, Christopher Kreitler (The University of Arizona., 1999)
      I examined trends in relative abundance and species richness of breeding and wintering grassland birds before (1996) and after (1997, 1998) a spring prescribed burn in a mesquite-dominated desert grassland at Buenos Aires National Wildlife Refuge, Arizona. The burn was moderate in intensity, patchy in extent, and affected ground cover more strongly than shrub cover, smaller shrubs more strongly than larger shrubs, and killed 1% of velvet mesquite (Prosopis velutina). Species richness of breeding birds decreased in the first year post-burn. Of breeding species, black-throated sparrows (Amphispiza bilineata) and mourning doves (Zenaida macroura) increased; whereas Botteri's sparrows (Aimophila botterii), Cassin's sparrows (Aimophila cassinii), and pyrrhuloxias (Cardinalus sinuatus) decreased in relative abundance. Breeding species characterized as not shrub-dependent exhibited changes that were more pronounced than those for shrub-dependent species. Of wintering birds, ladder-backed woodpeckers (Picoides scalaris) and vesper sparrows (Pooecetes gramineus) increased, and cactus wrens (Campylorhynchus brunneicapillus) decreased in relative abundance.
    • Trends in marking systems

      Wilson, Glenn, 1907- (The University of Arizona., 1940)
    • Trends in the Chilean short story

      Gregg, Karl Curtiss, 1932- (The University of Arizona., 1954)
    • Trends in the school laws of Arizona since statehood

      Zimmerman, Ralph Howe, 1901- (The University of Arizona., 1934)
    • Trends in the teaching of history

      Kitt, Ethel, T. (The University of Arizona., 1933)
    • Trevisa's translation of the mathematical section of Bartholomew's De proprietatibus rerum

      Dederich, Robert Marwood, 1916- (The University of Arizona., 1941)
    • Trialkoxyethylenes: a new class of reactive comonomers

      Papanu, Victor Dennis, 1950- (The University of Arizona., 1974)
    • Triangular plate model for nonlinear stress analysis

      Callabresi, Melvin LeRoy, 1939- (The University of Arizona., 1967)
    • Tribal and individual American Indian trust funds: Who's in charge?

      Wilkins, David E.; Cook, Tracey Suzanne (The University of Arizona., 1999)
      The United States Government has allegedly mismanaged Individual Indian Money and Tribal Trust Fund accounts since their creation over 150 years ago. Despite what appears to be a well-documented and incontrovertible body of evidence: extensive governmental and private sector audits, as well as congressional and executive level reports and hearings confirming chronic mismanagement, the BIA continues to lose, misplace, and often fails to collect millions in royalty payments belonging to Indian people without an equitable solution. Consequently, this thesis examines the most recent reform effort, the 1994 American Indian Trust Fund Mismanagement Reform Act offered by the 103rd Congress, the Strategic Plan created by the Office of Special Trustee, and finally, federal and tribal responses to the proposed Strategic Plan. The impact of these varied responses has elucidated several hindrances to effective reform, thus generating key questions which necessitate closer examination in order to advance effective reform.
    • Tribal Colleges and Universities: Beacons of Hope, Sources of Native Pride

      Tippeconnic Fox, Mary Jo; Smith, Kestrel A.; Tippeconnic Fox, Mary Jo; Begay, Manley Jr.; Oberly, Stacey (The University of Arizona., 2014)
      This study examines whether Tribal Colleges and Universities impact hope and pride within their surrounding communities. As part of the investigation, data was gathered through the distribution of a ten question survey to three participants at both Diné College and Comanche Nation College: the president, a student, and a community member. Further data was collected through testimonials gathered from articles within the Tribal College Journal from the past six years (2008-2013). The goal of the study is to broaden the understanding of Tribal College and University impacts within their communities, and to provide valuable information for the college-community relationship throughout Indian Country.