Thesis (M.S.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 105-122). Also available on the World Wide Web.

Leaf surface area present on black cottonwood (Populus trichocarpa) and Douglas hawthorn (Crataegus douglasi) was measured indirectly using a point frame, photographs, and a canopy analyzer. Each was compared to directly measured leaf surface area. Six black cottonwood and 3 Douglas hawthorn shrubs were selected in 1996 and 9 black cottonwood and 3 Douglas hawthorn shrubs in 1997. Shrubs were selected based on size and isolation. Each indirect method was applied prior to removing a portion of leaves from each shrub. Shrubs were defoliated in 3 to 7 increments and leaf surface area of each was measured. After shrubs were completely defoliated increments of measured leaf areas were added to subsequently removed leaf areas to determine the measured leaf area present on a shrub each time indirect methods were applied. Measured leaf areas were paired with indirect method values and regression equations were developed. Correlation coefficients for regressions were 0.76 for black cottonwood and 0.70 for Douglas hawthorn for the point frame, 0.91 for black cottonwood and 0.79 for Douglas hawthorn for the photographs, 0.62 for black cottonwood and 0.61 for Douglas hawthorn when shrub volume was included for the canopy analyzer. Photographs took 20 minutes to set up and take pictures followed by 1.5 hours for processing images in Idrisi and Picture Publisher. The point frame required 45 minutes to 1.5 hours field time and 5 to 10 minutes to process data. The canopy analyzer was the most rapid of the techniques requiring less than 5 minutes to secure a field measurement and enter this value into the regression equation. Canopy analyzer reliability was the lowest of the methods studied. / Graduation date: 1999

Graduation date: 1997

Thesis (Ph. D.)--Oregon State University, 1999. / Typescript (photocopy). Includes bibliographical references (leaves 101-118). Also available on the World Wide Web.

No description available.

Thesis (M.S.)--University of Alabama at Birmingham, 2006. / Description based on contents viewed Feb. 12, 2009; title from PDF t.p. Includes bibliographical references (p. 40-41).

The black cottonwood, Populus trichocarpa, provides the foundtaion for the riparian woodlands throughout southern British Columbia (B.C.) and western Montana (MT). To study the interaction of riparian dynamics and cottonwood ecology, the present study investigated the influence of the extreme 1995 Elk River flood on the riparian zone and cottonwood ecology, and the effects of flood flow attenuation by the Libby Dam on riparian processess and cottonwoodland ecology of the Kootenai(y) River. Four river reaches were studied: the free-flowing Elk River near Fernie, B.C., the free-flowing Upper Kootenay River, B.C., upstream from the Koocanusa Reservoir, the free-flowing Fisher River, MT, near the Kootenai junction, and the flow-attenuated Lower Kootenai River near Libby, MT. Air photos from 1930, 1962, 1992 and/or 1994 revealed substantial channel change and the development of barren point bars that served as recruitment sites for willos and cottonwoods along the free-flowing reaches. Conversely, the Lower Kootenai had a relatively static channel after damming. In total, thirty-five transects were studied in 1996 and 1997 at 3 sites along each river reach to assess elevation profiles, substrate composition, scour and deposition, vegatation patterns, and aspects of cottonwood reproduction. Abundant cottonwood recruitment occurred in 1996 and even more so in 1997, producing mean densities of 153, 536, and 142 seedlings/m2 along the Elk, Upper Kootenay, and Fisher river transects, respectively. In marked contrast, no seedlings were successful along the Lower Kootenai River, downstream from the Libby Dam. The free-flowing river reaches experienced extensive sediment deposition in the riparian zone after the 1997 high water, whereas the Lower Kootenai experienced little change in stream bank configuration. The Elk River study revealed that the 1995 flood caused considerate geomorphic change and the resultant unconsolidated deposits were easily scoured and transported during the subsequent two years providing abundant sites for new cottonwoods. The Kootenay River study revealed limited meandering and deposition along the flow-attenuated Lower Kootenai River compared to the hydrologically, geomorphologically, and ecologically dynamic, free-flowing upstream reach. Along the Lower Kootenai River, there was a deficiency in black cottonwood population age structure due to limited recruitment. Flood-intolerant, upland plants have encroached to the river's edge, further eliminating cottonwood recruitment opportunities along the Lower Kootenai River. The vegetation encroachment, the static channel configuration, the minimal scour and sediment deposition and the lack of the essential stream stage pattern, combine to underlie the lack of seedling recruitment and the consequent deficiency in cottonwood population structure along the Lower Kootenai River. The studies demonstrate that black cottonwoods require a dynamic hydrologic and geomorphic system with periodic flood events for continued replenishment. The observed loss of cottonwood recruitment along the Lower Kootenai River is thus the consequence of the flood flow attenuation due to the operation of the Libby Dam. The restoration of the Lower Kootenai cottonwoods will probably rely on a partial recovery of more natural and more dynamic instream flow patterns that include occasional high flows in late spring followed by gradual stage recession. Such flows would exclude upland vegetation, recover more dynamic geomorphic processes and provide the stream stage patterns that are directly essential for cottonwood seedling recruitment. / 1 v. (various pagings) : ill. (some col.), maps ; 28 cm.

Western juniper and cinnamon essential oils were combined with ethanol at 2.5, 5, and 10% concentrations by weight and applied to hybrid poplar (Populus trichocarpa x P. deltoids) veneers by vacuum soaking to produce a naturally durable wood veneer with increased mechanical properties for use in structural composites. Half of these veneers were then modified using viscoelastic thermal compression to increase veneer density and modulus of elasticity. Following densification, unprocessed and VTC processed veneers receiving an essential oil treatment were subjected to an AWPA E21-06 Formosan termite exposure test, AWPA E24-06 mold box test, and brown rot (Gloeophyllum trabeum) decay bending test. While VTC processing drastically reduced the abundance of chemical components inherent within essential oil treatments, veneer specimens without VTC processing showed increased durability. A 10% juniper oil treatment drastically reduced Formosan termite attack on hybrid poplar veneers while a 10% cinnamon oil treatment significantly reduced mold growth. Timbor��, an industrial powdered borate treatment, withstood VTC processing and inhibited Formosan termite attack and mold growth. Tests to evaluate the effectiveness of essential oil treatments against brown rot were unsuccessful. Results suggest that incorporating a disodium octaborate tetrahydrate (DOT) treatment prior to VTC processing could help improve VTC wood durability. / Graduation date: 2013

Thesis (Ph. D.)--Institute of Paper Chemistry, 1967. / Includes bibliographical references (p. 79-81).

Black Cottonwood (Populus trichocarpa) is a fast-growing, economically important tree species. P. trichocarpa was the first tree to have its genome fully sequenced and is considered the model organism for genomic research in trees. Of the macronutrients in plants, Nitrogen (N) is required in the greatest amounts and is generally the limiting nutrient in terrestrial ecosystems. Inorganic N-transport is performed by four families of transporter proteins, AMT1 and AMT2 for ammonium (NH4+) and NRT1 and NRT2 for nitrate (NO3-). I have created phylogenetic reconstructions of each of these transporter families in 22 members of Viridiplantae whose genomes have been fully sequenced. Based on these phylogenies, I have introduced a new classification system for the transporter families that better represents the evolutionary and functional relatedness of the proteins. These phylogenies were supplemented with topology predictions, subcellular localization predictions, and in silico expression profiling in order to suggest functional characterization of the groups. This facilitated candidate gene selection for NH4+ and NO3- uptake transporters from P. trichocarpa. Expression profiling was performed on two of these candidates. Results suggest that PtAMT1-1 may be a high-affinity, root-localized NH4+ transporter. In contrast, PtNRT2-6 is a high-affinity NO3- transporter localized to the dormant bud, but its physiological functions remain largely enigmatic. Flux profiles of NH4+, NO3-, and H+ in the first 1.4 cm of root tips of three-week-old P. trichocarpa seedlings and cuttings were measured using the Microelectrode Ion Flux mEasurement (MIFE) system to demonstrate the activity of AMTs and NRTs under nutrient-abundant and nutrient-deficient conditions. I found mainly N-efflux from roots of cuttings while seedling roots exhibited N-uptake. This is the first report of such a difference. This highlights an unexpected but clear physiological difference between seedling and cutting roots, which are frequently used in experimental setups. / Graduate / 0817 / 0369 / 0715 / neilvonw@gmail.com