This research examines the influence of western dwarf mistletoe (Arceuthobium campylopodum) infection on the radial growth response of mature ponderosa pines (Pinus ponderosa) and its effects on dendroclimatic reconstructions. I hypothesize that trees with mistletoe have lower annual growth rates than uninfected trees, but exhibit higher mean sensitivities and stronger relationships between growth and climate variation. I tested these hypotheses using correlation and regression analyses to compare 100-year crossdated and standardized tree-ring chronologies from 26 infected and 29 uninfected trees. I compared both chronologies to climate variation as measured by changes in total precipitation, minimum, mean, and maximum temperature, and the Palmer Drought Severity Index (PDSI). Results show that trees infected with dwarf mistletoe have higher radial growth rates, exhibit greater sensitivity, and respond more strongly to climate variation. Both infected and uninfected chronologies are significantly correlated with the respective climate variables, but exhibit different patterns. The strongest correlations are between infected trees and PDSI for all months tested; significant correlations between uninfected trees and PDSI are limited to May through December lagged from the previous year. These results suggest mistletoe-infected trees are more sensitive to climatic factors than uninfected trees and may be useful for dendroclimatic analyses.

Graduation date: 1994

To make low grade lumber into high-valued products, finger-jointing is a widely used method in the timber industry. In certain situations, chip-out occurs degrading the quality of the joint. To better understand the machining process, a beam-type dynamometer based on strain gages was designed to analyze the dynamic cutting forces parallel and vertical to the feeding direction. The test results indicate that the dynamometer design was sensitive enough to measure small force changes at relatively high frequencies during the cutting operation. The test conditions were set as close as possible to that in industry. Cutting force behavior of the rotating cutterhead was examined, and test samples with different fiber angles were used for inspecting the influences on the chip-out occurrence and cutting forces. The results show that cutting forces are determined by the density of the wood and the maximum chip thickness. Slight differences in tool shape and the balance of the cutterhead can vary the cutting force behavior. The occurrence of chip-out is dependent on the fiber angle and the chip thickness. No relationship between chip-out and cutting force was found, within the sensitivity of the dynamometer. Fiber angle has some effect on the cutting force, and also influences the cutting surface quality. A high speed video camera was also employed to visually observe the formation of chip-out. Frame by frame analysis showed that the chip-out occured when a knife passed through the trailing edge of the cut-block, and the failure developed in the sequel cuts. Cutting force and chip-out models were developed from the experiment results, and can be used to reduce chip-out and increase recovery during finger-jointing in ponderosa pine cut-stock operation. / Graduation date: 1993

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Thesis (M.S. - Watershed Management)--University of Arizona. / Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 210-228). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State College, 1958. / Typescript. Includes bibliographical references (leaves 91-95). Also available on the World Wide Web.