• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2
  • Tagged with
  • 10
  • 10
  • 5
  • 5
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Piñon Ips Bark Beetle

DeGomez, Tom 03 1900 (has links)
5 pp. / Pine Bark Beetles, Cypress Bark Beetles / Hosts, description and life cycle of the pinon ips and signs of infection. Management practices include maintaining tree health, sanitation and chemical sprays. Thinning is the long term solution to stressed stands. Many ecological factors are significant when managing for pinon ips.
2

The Piñon Ips Bark Beetle

DeGomez, Tom, Celaya, Bob 03 1900 (has links)
Revised; Original Published: 2006 / 5 pp.
3

Catastrophic Wildfire Hazard Assessment in Pinyon-Juniper Woodlands Utilizing a Managerial Paradigm

Baldwin, Benjamin D. 01 May 2003 (has links)
The impetus for this research was the increasing threat of catastrophic wildfires resulting from the accumulation of fuels across the West. Guided by the priorities, goals, and guiding principles outlined by the national fire plan (NFP), the objective was to identify those areas within a pinyon-juniper woodland-dominated landscape with the highest hazard of catastrophic wildfire. The intent was to help managers prioritize proactive fuels management efforts outside of the wildland urban interface (WUI). Based on a management paradigm, constraints were placed on the data collection, analysis, and model development. A geographic information system (GIS) was used to create a hazard assessment at a landscape scale in Tintic Valley, Utah. Hazard categories were a classification of fuels based on crown cover of pinyon-juniper trees, utilizing remotely sensed data. The data set consisted of digital orthophoto quadrangle (DOQ) images from 1993. The methods were developed in three phases. Phase One resulted in a hazard assessment protocol. In Phase Two, data layers were created to further divide the hazard categories into more tractable management units. Phase Three, through the retrospective examination of recent wildfires, indicated the limitations and utility of the assessment technique. The protocol presented provides a relatively fast, inexpensive, and timely hazard classification technique for pinyon-juniper woodlands at a watershed level. It is intended to be used for coarse-scale assessments of fuel hazards for strategic planning purposes. While not appropriate for fire behavior predictions, this assessment can focus managerial efforts for additional tactical planning.
4

Effects of Livestock Grazing on Infiltration and Erosion Rates Measured on Chained and Unchained Pinyon-Juniper Sites in Southeastern Utah

Busby, Frank E., Jr. 01 May 1977 (has links)
The objectives of this study were to 1) determine the effects of livestock grazing and periods of rest from grazing on infiltration and erosion rates of unchained woodland; chained, debris-in-place; and chained, debris-windrowed pinyon-juniper sites; and 2) utilize these measurements in developing guidelines for grazing management of pinyonjuniper rangelands that protect or improve the hydrologic condition of the watershed. The study was conducted on sandy loam soils in southeastern Utah during the summers of 1971 and 1972. Runoff and erosion were artificially induced from small plots by simulating rainfall with the Rocky Mountain infiltrometer. Infiltration rates, erosion rates, and selected vegetative and edaphic parameters were measured on each plot. Forage removal by clipping and soil compaction subtreatments were applied to randomly selected plots in an effort to simulate the forage removal and trampling activities of livestock. Analysis of variance techniques were used to determine the effect on infiltration and erosion rates of forage removal and soil compaction subtreatment, grazing and varying periods of rest from grazing, and chaining treatments with similar grazing histories. Multiple regression techniques were used to evaluate the influence of vegetative and edaphic factors on infiltration and erosion. Forage removal and soil compaction subtreatments had no consistent effect on infiltration rates. However, the clipping and compaction subtreatments were an instantaneous application of forage removal and soil pressure and thus may not adequately represent long term, accumulative conditions imposed by actual grazing. Areas rested from livestock grazing since 1967 had significantly higher infiltration rates than grazed areas on unchained woodland and chained, debris-in-place sites. Grazed plots consistently had the lowest infiltration rates although this lower rate was not significantly different from infiltration rates measured on areas protected from grazing since 1969 or 1971. Grazing did not consistently affect infiltration measured on chained, debris-windrowed sites. Infiltration rates increased on all three vegetative conditions as the period of rest from grazing increased. None of the 21 soil and vegetative variables included in this study were identified by multiple regression models as consistently explaining significant amounts of variation in infiltration rates. Results of this study indicate that the primary value of multiple regression models is not to predict changes that will occur in infiltration because one management alternative is selected over another, but to help explain significant differences measured between treatments. Erosion rates were not significantly affected by forage removal subtreatments, but a trend indicates that erosion increases on plots when above ground vegetation is removed by clipping. No consistent relationship between -erosion rates and soil compaction subtreatments was found. A trend toward increased erosion rates on grazed areas was found. No consistent relationship between erosion rates and the various periods of rest from grazing was recorded. Thus, any rest from grazing appears to reduce the erosion potential from pinyonjuniper sites. In summary, pinyon-juniper rangelands can be improved for livestock by chaining and seeding without causing a deterioration in watershed condition. However, to achieve these objectives, the sites to be treated must be carefully evaluated and the appropriate chaining, plant debris disposal, and seeding techniques identified. And following vegetative conversion, the areas must be properly grazed.
5

Mule Deer Use Patterns as Related to Pinyon-Juniper Conversion in Utah

Terrel, Ted L. 01 May 1973 (has links)
Objectives were (1) to evaluate the seasonal and daily use by mule deer (Odocoileus hemionus) of adjoining converted and natural pinyon pine-Utah juniper woodland (P-J) winter range, and (2) to determine the major factors influencing mule deer use of converted P-J range to provide criteria for deer management. The study was conducted on 3 sites in central, eastern, ar.d southeastern Utah between 1969-72. Data for 1969-72 on physiographic, climatic, and vegetational attributes of the three Utah study areas were related to data from approximately 10,000 deer observations, 5,000 0.01-acre pellet-group count plots, feeding observations of 1,100 deer, 220 miles of track counts on trails, and 450 radio locations of nine adult female deer. Conclusions were: (1) In the initial 12 years post-treatment, no increase in deer numbers X was correlated with P-J conversion. (2) Increasing deer use during the study was concentrated on natural P-J. (3) The bulk of the use on chainings occurred in March and April. (4) Radio telemetry indicated that, from November to May, about 55 percent of the deer within 0.5-mile of the chaining edge used the chainings at night, and 5 percent in the day. (5) Deer fed and bedded in alternate 2-hour periods. Thus, the Mayfield chainings contributed 25 to 30 percent of the deer forage, but comprised over 50 percent of the land area. (6) The greatest overwinter deer use occurred in shallow valleys and on slopes of 10-20°. Least preferred by deer were flats and hilltops. Chaining decreased the relative deer use on hilltops, increased it on hillsides, and had no effect on the use of valleys. (7) Deer use was greatest on north exposures in the natural P-J and on south exposures on chainings. (8) No edge effect existed in the initial mile of P-J away from the chaining edge, whereas, deer use of chainings declined 50 percent in the initial 0.2-mile. (9) Radio telemetry showed a mean home range radius of 0.6- mile between November and May for nine adult female deer. (10) Moon phase effected deer use on the chainings but with reversed influence between November and May. (11) Snow cover over 10 inches and wind velocity greater than 20 miles-per-hour each decreased considerably deer use of chainings. (12) An increase in shrub density increased deer use of chainings more than any other variables measured. (13) Chaining of P-J apparently decreased Cercocarpus montanus, Quercus gambelii, and Pinus edulis shrub density but increased Juni£eru~ osteosperma and Artemisia spp. Forb cover did not markedly change post-chaining, while grass cover increased by 400 percent. (14) Total forage crown cover increased 25 percent 3-12 years post-treatment. However, total palatable browse cover was less on treated than untreated range. (15) Juniperus spp., Artemisia spp. and green grasses comprised 60 to 75 percent of the over-winter diet; the remainder was composed largely of Quercus gambelii and Cercocarpus montanus. (16) Optimum tree density for deer use of P-J appears to be 50 to 100 per acre, depending upon maturity of the stand. Management recommendations are that P-J chainings should: (1) be less than 0.4-mile wide, compose no more than 20 percent of the winter range 1n a 25 year period, (2) be single chained only, (3) be confined to small valleys and gentle slopes, (4) have 20 percent slash cover, 5-10 percent grass cover, and many of the pushed-over tree tops ~eft alive, (5) be confined largely to south and west exposures, (6) be grazed in a spring- fall rotation by cattle.
6

Conventional and Catalytic Pyrolysis of Pinyon Juniper Biomass

Yathavan, Bhuvanesh Kumar 01 December 2013 (has links)
Pinyon and juniper are invasive woody species which has occupied more than 47 million acres of land in Western United States. Pinyon juniper woodlands domination decreases the herbaceous vegetation, increase bare lands which in turn increases soil erosion and nutrition loss. Thus, The US Bureau of Land Management (BLM) has focused on harvesting these woody species to make room for herbaceous vegetation. The major application of harvested pinyon-juniper (PJ) is low value firewood. Thus, there is a need to develop new high value products from this woody biomass to reduce the cost of harvesting. In this study pyrolysis was carried out to investigate the feasibility of converting pinyon juniper biomass to value added products. The first part of the study was focused on biomass characterization, and effect of biomass type on product yields. The second part focuses on optimization of process parameters on product yields. The third part focuses on catalytic pyrolysis for improving the quality of bio-oil. In this study it has been shown that pinyon juniper biomass could be effectively used as biomass in fast pyrolysis and red mud, an industrial waste could be used as catalyst in catalytic pyrolysis to improve the quality of the bio-oil.
7

Selecting Optimum Conversion Practices in the Pinyon-Juniper Type

Marasco, Richard J. 01 May 1966 (has links)
A profit criterion which will make possible the selection of optimum conversion practices in the Pinyon-Juniper woodlands can be made operational if: (a) it is possible to predict eradication costs and resulting total costs (eradication costs, seed costs, and seed application costs) , and (b) it is possible to determine for age production resulting from initial eradication, as well as when it reaches absolute minimum allowable limit due to tree re-growth . Knowledge of the above relationships makes it possible to determine the optimum practice.
8

Fuel Response to Mechanical Mastication of Pinyon-Juniper Woodlands in Utah

Shakespear, Alan Wyatt 01 December 2014 (has links) (PDF)
Pinyon-juniper woodland encroachment threatens ecosystem function and diversity on sagebrush steppe. Decreased fire frequency likely favors proliferation of pinyon-juniper woodlands and subsequent decline in desirable understory species. Increased tree cover produces hazardous canopy fuel loads that contribute to severe crown fires and threaten life and property at the wildland-urban-interface. Mechanical mastication converts large canopy fuels into small woody debris, altering wildfire dynamics from a potential crown fire to a more controllable surface fire. We measured fuel loading and cover on untreated, masticated, and masticated + burned treatments on 30-m transects within 30 X 33-m subplots, representing 45 different sites throughout Utah. All variables were analyzed using mixed-model analysis of covariance with untreated or pretreatment tree cover as the covariate. Shredding trees reduced large-diameter fuels to primarily 10-hour fuels (6.4-25.4 mm diameter). Reduced fuel sizes, fuel redistribution, and fuelbed compactness resulting from mastication treatments can aid wildfire suppression. Masticated + burned treatments effectively reduced woody surface fuel loading to that of pretreatment conditions. Prescribed burning could be used outside the growing season in cool-weather, high-moisture conditions to remove surface fuels, mitigating lethal soil heating and plant mortality. Shrub loading was not adversely affected by mastication treatments, but was significantly reduced with masticated + burned treatments. Masticated and masticated + burned treatments significantly increased herbaceous fuel loading. Treating at lower tree cover values reduced fuel buildup, and provided more opportunity for a positive herbaceous response. Fuel loading estimates measured in this study were provided to populate fire behavior models for mastication treatments on our study sites when such models become available.
9

Descriptions, Ecological Associations and Predictive Species Distribution Models of New Species of Psilochalcis Kieffer (Hymenoptera; Chalcididae) Occurring in Utah's Eastern Great Basin

Petersen, Mark J. 18 April 2023 (has links) (PDF)
The genus Psilochalcis, of the Family Chalcididae, was originally described in 1905 by Kieffer. Mainly considered an Old-World taxon, the first North American Psilochalcis were not identified until 1981 by Grissell and Schauff. Little is known about the species distributions, biologies and ecological relationships of these parasitic wasps. This dissertation describes research conducted in central Utah setting arrays of Malaise traps in 4 different habitat types common to the Great Basin at three separate locations. A result of this sampling revealed a high abundance of multiple species of Psilochalcis wasps, particularly from one location and two habitat types. Chapter 1 describes three new species of Psilochalcis wasps namely; P. adenticulata Petersen, P. minuta Petersen, and P. quadratis Petersen. A review of all North American Psilochalcis species explains their distribution in Utah and throughout the surrounding western United States. A taxonomic key for all North American Psilochalcis species is given. Chapter 2 examines the seasonal abundance of P. minuta and P. quadratis and their associations with two common Great Basin habitat types. Both species show their highest abundance from late June through early August. Their peak abundance is shown to change dependent on the environmental conditions of temperature and precipitation. Psilochalcis minuta is significantly associated with pinyon/juniper (Pinus edulis or P. monophylla and Juniperus osteosperma) and P. quadratis is significantly associated with cheatgrass (Bromus tectorum). Chapter 3 describes the building of species distribution models for P. minuta and P. quadratis using a maximum entropy (Maxent) approach. Ten environmental variables were used to predict areas of optimal suitable habitat for each species. Multiple predicted sites were field sampled to test each model's effectiveness. Psilochalcis minuta occurred at nearly 90% of predicted sites, and P. quadratis occurred at 50% of predicted sites. Both species occurred at some non-predicted sites in other habitat types. Model analyses and field-testing results show the P. minuta model to be reliable in predicting areas of probable species occurrence, while the P. quadratis model is much less reliable in doing so. Aspect and fire disturbance show the highest percent contribution to both species' models. Slight differences in variable percent contribution between models suggest these species have sympatric distributions. Soil and slope are more important predictors of optimal suitable habitat for each species. Maintaining integrity between model predictions and field testing gave insights into other factors contributing to probable occurrence of Psilochalcis species.
10

An Object-Based Image Analysis of Treated and Untreated Pinyon and Juniper Woodlands Across the Great Basin

Hulet, April 07 March 2012 (has links) (PDF)
Land managers need to rapidly assess vegetation composition and bare ground to effectively evaluate, manage, and restore shrub steppe communities that have been encroached by pinyon and juniper (P-J) trees. A major part of this process is assessing where to apply mechanical and prescribed fire treatments to reduce fuel loads and maintain or restore sagebrush steppe rangelands. Geospatial technologies, particularly remote sensing, offers an efficient option to assess rangelands across multiple spatial scales while reducing the need for ground-based sampling measurements. High-spatial resolution color-infrared imagery (0.06-m pixels) was acquired for sagebrush steppe communities invaded by P-J trees at five sites in Oregon, California, Nevada, and Utah with a Vexcel Ultra CamX digital camera in June/July 2009. In addition to untreated P-J woodlands, imagery was acquired over P-J woodlands where fuels were reduced by either prescribed fire, tree cutting, or mastication treatments. Ground measurements were simultaneously collected at each site in 2009 on 0.1-hectare subplots as part of the Sagebrush Steppe Treatment Evaluation Project (SageSTEP). We used Trimble eCognition Developer to 1) develop efficient methods to estimate land cover classes found in P-J woodlands; 2) determine the relationship between ground measurements and object-based image analysis (OBIA) land cover measurements for the following classes: trees (live, burned, cut, and masticated), shrubs, perennial herbaceous vegetation, litter (including annual species), and bare ground; and 3) evaluate eCognition rule-sets (models) across four spatial scales (subplot, site, region, and network) using untreated P-J woodland imagery. At the site scale, the overall accuracy of our thematic maps for untreated P-J woodlands was 84% with a kappa statistic of 0.80. For treatments, the overall accuracy and kappa statistic for prescribed fire was 85% and 0.81; cut and fell 82% and 0.77, and mastication 84% and 0.80, respectively, each indicating strong agreement between OBIA classification and ground measured data. Differences between mean cover estimates using OBIA and ground-measurements were not consistently higher or lower for any land cover class and when evaluated for individual sites, were within 5% of each other; all regional and network OBIA mean cover estimates were within 10% of the ground measurements. The trade-off for decreased precision over a larger area (region and network scale) may be useful to prioritize fuel-management strategies but will unlikely capture subtle shifts in understory plant communities that site and subplot spatial scales often capture. Although cover assessments from OBIA differed somewhat from ground measurements, they were accurate enough for many landscape-assessment applications such as evaluating treatment success and assessing the spatial distribution of fuels following fuel-reduction treatments on a site scale.

Page generated in 0.0599 seconds