No description available.

No description available.

No description available.

No description available.

No description available.

The types of wood identified from tree -ring specimens of 78 archaeological sites in the area of Flagstaff, Arizona were analyzed for changes through time. The sites span a period from Basketmaker III through Pueblo III times. Most of the specimens are from constructional materials. The wood identifications were also compared with the tree types growing on the sites today (1960). The analyses show that there is a great uniformity of types of wood used and the relative percentages of the various woods throughout the time span. This uniformity exists regardless of the location of the site geographically, or in relation to the modern tree distribution. Only the sites constructed during Pueblo I times are different. This group is restricted to the present ponderosa pine limits, and they did not yield a single specimen of either juniper or oak, both of which are found in all the other time divisions. Douglas fir, ponderosa pine, piñon pine and Populus sp. occur in relatively consistent percentages throughout the time span, despite the change in dwelling type from pithouses to pueblos. Since the Indians used trees other than those closest at hand for building purposes, they had to haul large quantities of wood from the areas where the trees grew. Distances to the nearest places where the wood types can be found today are as much as 15 miles from the sites. Some strong motivation must have inspired so great an expenditure of effort, but the reason is not apparent.

No description available.

Increment cores were collected from 10 stands in mixed-conifer forest stands which had suffered varying levels of Douglas-fir tussock moth defoliation during 1946, 1964, and 1973 infestations in north central Idaho. Ring-width measurements, standardized to remove inherent growth trends, were compared between host (Douglas-fir and grand fir) and nonhost (western larch, ponderosa pine, western white pine) species for evidence of growth losses due to defoliation. Heavy defoliation caused growth of host species to decrease 75 %-90% in one year. Normal growth rates returned within 3-4 years after maximum defoliation, however. The effect of moderate defoliation could not be reliably identified in the data.

When coring thick-barked trees, increment cores often become compressed and jammed inside the narrow region of the borer shaft. These jams can be problematic for two reasons: first, it often leaves the core unusable; second, the jam may be so tightly compressed in the borer that removal is difficult, especially in the field. Although procedures to evacuate these jams are documented in the literature, methods of prevention are not. Here, a modified manual method of increment boring that can reduce the likelihood of jams and, in addition, decrease the number of deformed core samples is described. Traditional and modified boring methods were randomly assigned to 40 Douglas-fir trees (80 cores) at a research site along the Oregon coast. Results show that jams were associated with traditional boring over six times more than with the proposed modified technique.

The purpose of this study was to determine the effects of task difficulty on the amplitude and latency of the P300 by altering the intensity of the oddball stimulus. A P300 was obtained on 22 adult subjects ranging in age from 21 to 34 years of age (mean = 24 years) with normal hearing. The "frequent stimulus" was a 1000 Hz or 4000 Hz tone burst, gated with a rise and fall time of 10 msec and 20 msec plateau, presented at 75 dBn HL The "oddball stimulus" was a tone burst of the same frequency (1000 Hz or 4000 Hz)presented at 77, 79, or 81 dBn HL. A four-channel recording was made with linked reference electrodes and the following montages:Cz-A1+A2, Pz-A1+A2, and Fz-A1+A2. The fourth channel was used to monitor "eye blink" activity. The investigation tested the null hypothesis that changing the intensity of the oddball stimuli would not result in a significant change in either the amplitude or latency of the P300. Analyses of Variance (ANOVA) indicate that P300 latency and amplitude did not differ significantly by run, stimulus frequency, intensity of the oddball, or montage. Thus the null hypothesis was supported.