This study investigated the potential use of wide skidder tires for forest harvesting operations on steep slopes. During the summer of 1984, field tests were conducted to compare the performance characteristics of 24.5-32 and 66-43 rubber tires on a JD-640 grapple skidder loaded with tree length material. The skidder was operated on 20%, 25% and 30% slopes on Piedmont soils near Rome, Georgia. Video recorders were used to document the field measurements and observations of machine travel time and wheel slip over defined courses. Soil compaction was evaluated by comparing soil cone penetrometer readings taken in the wheel tracks of the test lanes to those taken in undisturbed adjacent areas. Skidder lateral stability was analyzed using the mathematical model developed in this study. Based on the results of statistical analyses of the data and field observations obtained under the test conditions, the skidder equipped with wide tires generally attained higher average speeds, tended to cause less wheel slip, resulted in smaller increases in soil cone penetrometer readings, and had significantly greater stability on sideslopes than the skidder equipped with the narrow tires. The stability model developed in this study predicted the critical sideways tipping angle for a JDâ 64O grapple skidder to be approximately 32° when fitted with the 24.5-32 tires, and 44° when fitted with the 66-43 tires. / Master of Science

The logging industry of the Amazon is a topic that has received little attention in the literature, beyond specific single firm case studies. This has not allowed estimation of cost and production functions that can be used to predict changes in the industry in response to external market factors or government policies. Cost functions and rents are very important to characterize the dynamics of industry behavior, as well as providing important information for future policies. This study relies on a survey of 527 firms to estimate harvest, transportation, and milling cost functions for the logging industry in the Brazilian Amazon, finding variables such as labor cost, distance from the forest to the sawmill, equipment and frontier type to significantly affect the total and marginal cost of each activity. Rents are also estimated for different sampled milling centers, and a cost minimizing mathematical programming model is presented that explains the advance of the logging frontier in Brazil. / Master of Science

The aim of this research was to identify promising areas for international cooperative development work in the area of integrated harvesting systems which incorporate the recovery of logging residues. The Harvesting Analysis Technique, a computer simulation package, was used to model seven harvesting systems on forest stands in five participating countries. The simulation results indicated that on good terrain with short skidding distances mechanical felling and grapple skidding was the best available method to deliver full trees to a landing. Processing trees at the landing accounted for at least 50 percent of the harvesting cost, indicating that if full trees or tree sections could be efficiently transported on public roads, then centralized processing may be the best alternative. Where logging residues consisted primarily of cull trees, full tree chippers were found to be an effective means for comminution. Residues consisting of tops and branches are more problematic due to their small piece size, lack of uniform linear orientation, and low bulk density. Compaction prior to chipping was proposed as one possible solution to this problem. Alternatively, residue processing could be combined with the merchandising of the full tree. Five problem areas were identified which could be of interest for future international cooperative projects: 1. Compacting tree sections, full trees or residues on trucks. 2. Delimbing tree sections with a mobile unit. 3. Systems for handling and processing residues at a landing. 4. Integrated systems for processing full trees at a landing. 5. Chip fractioning techniques. In addition, the development of a standard format for data collection in equipment evaluations would expedite comparisons of equipment originating in different countries. / M.S.

I studied breeding birds and vegetation in 6 largely pristine old-growth ponderosa pine (Pinus ponderosa) stands and in 3 logged stands that just met the USDA Forest Service's minimum habitat quality standards for old-growth ponderosa pine. Bird populations were similar in all stands. However, brown creepers (Certhia americana) and hermit thrushes (Cattarus guttatus) were low in abundance or absent in 2 of the minimum stands, yet were common in all other stands. Both species preferred cool, moist microenvironments for nesting and/or foraging; conditions that appeared lacking in the more xeric minimum stands. Both species are characteristic of boreal forests, which are cooler and wetter than ponderosa pine forests. I suggest that unlogged old-growth ponderosa pine forests create microhabitats that approximate conditions in more boreal forests. The minimum standards on drier sites appear inadequate in maintaining creeper and thrush habitat. Suggested modifications of the standards include, among others, canopy cover ≥ 50%.

Ritmos biológicos e sua sincronização por ciclos ambientais geralmente são estudados em roedores, mantidos em laboratório. Nosso grupo vem estudando ritmos de atividade/repouso de roedores subterrâneos sul-americanos conhecidos como tuco-tucos (Ctenomys aff. knighti) em laboratório e campo. Na natureza, sabemos que os tuco-tucos emergem à superfície diariamente em episódios de até uma hora. Registros curtos da atividade de superfície dos tuco-tucos, anteriormente obtidos pelo grupo, haviam sugerido que o padrão diário das saídas variava sazonalmente, sendo crepusculares durante o verão e concentrados no meio do dia, durante o inverno. Esse mesmo padrão sazonal já foi observado em populações de outros roedores de deserto e foi atribuído a reações dos roedores às variações diárias de temperatura, no verão e inverno. Por outro lado, a sazonalidade dos padrões de atividade de várias espécies de mamíferos e aves também pode ser explicada pela sincronização diária do ritmo de atividade a diferentes fotoperíodos. O objetivo desse trabalho é caracterizar a variação sazonal dos ritmos diários de atividade dos tuco-tucos, com uso de bio-logging, e verificar a contribuição dos fatores ambientais para a sazonalidade desses padrões. Ao longo do ano, acelerômetros e luxímetros foram presos a 29 animais recentemente capturados (15 fêmeas e 14 machos). Cada animal foi mantido individualmente em arenas semi-naturais por um mês. Variáveis ambientais foram registradas simultaneamente. Outros 18 animais (9 fêmeas e 9 machos) foram mantidos em laboratório, expostos ao fotoperíodo natural e em ambiente com temperatura constante. Os resultados confirmaram a sazonalidade do padrão temporal de atividade de superfície dos tuco-tucos. Os acelerômetros se mostraram mais precisos e sensíveis a pequenos movimentos corporais do que os registros de telemetria encontrados na literatura. Esses sensores também revelaram padrões de atividade subterrânea e noturna, em ambiente semi-natural. Durante o verão, a atividade de superfície diária dos tuco-tucos foi melhor prevista pelo horário do dia (fator endógeno) do que pelas variações de temperatura ambiental (fator exógeno). Durante o inverno, entretanto, a temperatura ambiental teve maior contribuição no padrão de saídas dos tuco-tucos, indicando complexas contribuições dos fatores endógenos e exógenos no delineamento dos padrões de atividade / Biological rhythms and their synchronization by environmental cycles are generally studied in rodents, inside laboratory. Our group studies activity/rest rhythms of South American subterranean rodents known as tuco-tucos (Ctenomys aff. knighti), in laboratory and field. In nature, it is known that tuco-tucos emerge daily to the surface, in brief episodes. Short records of tuco-tucos\' individual surface activity, previously collected by our group, had suggested that daily temporal pattern of emergence varied seasonally, being crepuscular in summer and concentrated around midday in winter. The same seasonal pattern was observed in populations of other desert rodents and was attributed to daily variations of environmental temperature, in summer and winter. At the same time, seasonality of activity patterns of various species of mammals and birds can be explained by daily synchronization of the activity rhythm by different photoperiods. Our aim is to characterize seasonal variation of daily activity rhythms of tuco-tucos, using bio-logging, and to verify the contribution of environmental factors in the seasonality of these patterns. Throughout the year, accelerometers and luximeters were tied to 29 freshly caught animals (15 females and 14 males). Each animal was kept inside semi natural enclosures for one month. Environmental variables were recorded simultaneously. Other 18 animals (9 females and 9 males) were kept inside laboratory, exposed to natural photoperiod, in a room with constant temperature. We confirmed the seasonality of temporal pattern of surface activity of tuco-tucos. The accelerometers resulted to be more precise and sensitive to small body movements than telemetry records found in literature. They also revealed nocturnal and subterranean activity patterns inside the enclosures. During summer, daily surface activity of tuco-tucos was better predicted by time of day (endogenous factor) than by environmental temperature (exogenous factor). During winter season, however, environmental temperature has a stronger contribution on the emergence pattern in tuco-tucos, indicating complex contributions of endogenous and exogenous factors that outline activity patterns

Thesis (M.S.)--Oregon State University, 1975. / Typescript (photocopy). Includes bibliographical references. Also available on the World Wide Web.

This thesis explores two ways of developing a fracture diagnostics tool capable of estimating hydraulic fracture propped length and orientation. Both approaches make use of an electrically conductive proppant. The fabrication of an electrically conductive proppant is believed to be possible and an option currently on the market is calcined petroleum coke. The first approach for tool development was based on principles of antenna resonance whereas the second approach was based on low frequency magnetic induction. The former approach had limited success due to the lack of resonant features at the stipulated operating conditions. Low frequency induction is a more promising approach as electromagnetic fields showed measurable changes that were dependent on fracture length in simulations. The operation of a logging tool was simulated and the data showed differences in the magnetic field magnitude ranging from 2% to 107% between fracture sizes of 20m, 50m, 80m, and 100m. Continuing research of the topic should focus not only on simulating more diverse fracture scenarios but also on developing an inversion scheme necessary for interpreting field data. / text

Thesis (M.A.) - Simon Fraser University, 2006. / Theses (Dept. of Sociology/Anthropology) / Simon Fraser University. Includes bibliographical references (p. 139-148).

Thesis (M.S.)--Oregon State University, 2006. / Printout. Includes bibliographical references (leaves 82-87). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 102-110). Also available on the World Wide Web.