Show simple item record

dc.contributor.advisorTrouet, Valerieen
dc.contributor.authorShepard, Robert Michal
dc.creatorShepard, Robert Michalen
dc.date.accessioned2016-04-12T22:49:14Zen
dc.date.available2016-04-12T22:49:14Zen
dc.date.issued2015en
dc.identifier.urihttp://hdl.handle.net/10150/605122en
dc.description.abstractVelvet 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.
dc.language.isoen_USen
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en
dc.subjectgrowth curvesen
dc.subjectProsopis velutinaen
dc.subjectTree ringsen
dc.subjectvelvet mesquiteen
dc.subjectwood anatomyen
dc.subjectNatural Resourcesen
dc.subjectDendrochronologyen
dc.titleTree Rings In Velvet Mesquite (Prosopis velutina Woot.): An Exploratory Study of Wood Anatomy, Crossdating, Climate-Growth Relationships, Life History, and Above-Ground Biomassen_US
dc.typetexten
dc.typeElectronic Thesisen
thesis.degree.grantorUniversity of Arizonaen
thesis.degree.levelmastersen
dc.contributor.committeememberTrouet, Valerieen
dc.contributor.committeememberArcher, Steveen
dc.contributor.committeememberScott, Russen
dc.contributor.committeememberSheppard, Paulen
dc.description.releaseRelease 18-Aug-2016en
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineNatural Resourcesen
thesis.degree.nameM.S.en
refterms.dateFOA2016-08-18T00:00:00Z
html.description.abstractVelvet 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.


Files in this item

Thumbnail
Name:
azu_etd_14377_sip1_m.pdf
Size:
3.389Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record