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  • 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.
31

Facilitating Private Forestland Management: Relating Landowners’ Experience of their Forestland and their Conceptualization of Forest Management to their Management Behavior

Steiner Davis, Miriam L.E. 01 May 2008 (has links)
Privately owned forestland accounts for the majority of forested land in the US and provides numerous ecological, economic and social benefits to its owners and society at large. However, numerous issues ranging from fragmentation and parcelization, to pressure from the forest products industry, to increasing land values for development and real estate interests threaten to “unravel” the forest landscape. Active management of forestland is seen as one way to combat such threats. Active management of private forestland has been linked to numerous factors such as private forest landowners’ (PFLs’) general education level and familiarity with forest management, their goals, interests, objectives, attitudes, values, beliefs, and socio-cultural identity and the size and tenure of their ownership, among others. However, despite numerous efforts to understand private forest landowners (PFLs) and their interests, goals and objectives in owning private forestland, and to educate them about, and provide assistance for, private forest management, most privately owned forestland is not managed and most landowners remain unaware of the assistance and information available to them. In addition, the primarily quantitative studies investigating how these factors relate to private forestland management have been criticized for producing diminishing returns and insufficiently updating survey instruments. Using a mixed methods study design, including both quantitative and qualitative approaches, this study, conducted in the Emory-Obed watershed of East Tennessee, examined how the meaning of PFLs’ experience of their forestland and their conceptualization of forest management, two variables previously unaddressed in the literature, relate to PFL management behavior. Based on their experiences with their land, PFLs were found to form strong personal attachments to their land. Both the strength and the nature of these attachments varied relative to the degree to which PFLs actively engaged in forest management practices. The experience of those who actively engage in forest management activities is focused on the land and its condition, while the experience of those who do not actively engage in forest management activities is focused on themselves and how the experience makes them feel. Private forestland was also experienced as place. When these ways of experiencing forestland were quantified, a set of five components characteristic of the experience of forestland were identified: emotional connection to forestland, connection to nature via forestland, connection to family via forestland, forestland provision of PFL personal and financial gain, and forestland provision of financial investment. The more actively engaged with private forest land management PFLs were, the more strongly they agreed that each of these components was both meaningful and important to them. Landowners also varied in the ways in which they understood the forest management concept. Landowners simultaneously conceptualized forest management as property maintenance, as creating and enhancing forest habitat and as making money. As with the meaning of PFLs experience of their forestland, the more actively engaged in forest management activities PFLs were, the more strongly they agreed each of these components defined forest management. Lastly, the vast majority of PFLs participating in this study stated they believe they manage their forestland. This is in stark contrast to conclusions reported in the literature concerning the percentage of PFLs actually managing their forestland and is attributed in part to lack of standardization in the operationalization of forest management participation measures reported in the literature. Several implications of the findings for professional forestry practice, research, outreach and education are made based on recognizing the importance of the meaning of landowners’ experience of their forestland and their conceptualization of forest management to their interest in and engagement in forest management activities. For example, as the findings indicate PFLs may not see a relationship between the ways their forestland is meaningful to them and their understanding of what it means to manage their forestland, forest landowner educational opportunities and events capitalizing on the strong personal attachments PFLs feel to their land and utilizing language similar to their own ways of speaking about these attachments such as, “Getting to Know Your Woods”, “The Woods in Your Backyard: What’s There and Why You Should Care” and “Having Your Cake and Eating It Too: Enjoying and Profiting From Your Forestland” may prove more effective than traditional programs.
32

GENETIC DIVERSITY, STRUCTURE, AND RECOLONIZATION PATTERNS OF KENTUCKY BLACK BEARS

Hast, John Tyler 01 January 2010 (has links)
After nearly a century of absence, the black bear (Ursus americanus) reappeared in Kentucky during the late 20th century and has since increased in number. Recolonization of bears in the southeastern portion of the state was thought to have been caused by emigration of bears from adjacent states into the Commonwealth, while in the south-central area, bears originated, or natural recolonization may have been supplemented by the translocation of 14 individuals into the Big South Fork National River Recreation Area. To investigate the recolonization patterns of bears in Kentucky, I used 20 microsatellite loci to determine the genetic diversity and subpopulation structure of bears in the state, and quantified the relative influence of source populations of bears from neighboring states. Two genetically distinct populations of black bears were identified; Big South Fork and Cumberland Plateau. These populations were moderately diverged from each other and had levels of heterozygosity similar to other stable bear populations in North America. The Cumberland Plateau bear population originated from a combination of bears from both West Virginia and Virginia. In contrast, the Big South Fork population appeared to be almost entirely comprised of individuals from the translocated founders from Great Smoky Mountain National Park.
33

Growth of eucalyptus pellita in mixed species and monoculture plantations

Bristow, Mila Unknown Date (has links)
Eucalyptus pellita is a commercially important plantation hardwood species for the humid tropics of north Queensland. This species is favoured by both small-scale growers for use in mixed species woodlots targeting low-volume high-value sawn timber, and also by industrial forest companies growing monocultures for integrated pulp – sawn timber regimes. This study investigated whether mixed-species designs can increase the growth of this tropical eucalypt when compared to monocultures.A replacement series experiment with monocultures of Eucalyptus pellita (E) and Acacia peregrina (A) and mixtures in various proportions (75E:25A, 50E:50A, 25E:75A) was used to examine questions about growth and productivity. The trial was located on the Atherton Tablelands of north Queensland, Australia. High mortality in the establishment phase due to repeated damage by tropical cyclones altered the trial design. Effects of experimental designs on tree growth were estimated using a linear mixed effects model with restricted maximum likelihood analysis (REML). Volume growth of individual eucalypt trees were positively affected by the presence of acacia trees at age five years and this effect generally increased with time up to age 10 years. However, the stand volume and basal area increased with increasing proportions of E. pellita, due to its larger individual tree size. Conventional analysis did not offer convincing support for mixed-species designs. Preliminary individual-based modelling using a modified Hegyi competition index offered a solution and an equation that indicates acacias have positive ecological interactions (facilitation or competitive reduction), and definitely do not cause competition like E. pellita. These results suggest that significantly increased growth rates could be achieved with mixed-species designs over E. pellita monocultures. This statistical methodology could enable a better 4 understanding of species interactions in similarly altered experiments, or undesigned mixed-species plantations.The effects of trees on soils are highly variable and highly site and species specific. That trees can change soil chemistry over time is well established. The soil chemical properties under the eucalypt: acacia experiment were compared to several potential baseline data sources: the reference description of this soil type; those measured at 7 months after planting; and with those of soils under two adjacent vegetation types (forest and pasture) when the experiment was aged 9 years. At 9 years after planting soil total nitrogen increased with increasing proportion of acacias in the treatment. The mean total N under the acacia monoculture was significantly higher (P = 0.041) than that of either the eucalypt monoculture, or the surrounding pasture. The proportion of acacia in the treatment was positively linearly correlated with soil total N (r2 = 0.46; P = 0.018). Soils under the eucalypt monocultures were more similar to those under pasture for a range of soil chemical properties, compared with soils under treatments containing acacias. Results from this site show that the two species alter the soil chemistry in different ways. It is possible that the increased total N under the acacias could be facilitating the growth of the E. pellita, however without n-fixation analysis or tissue sampling it is not possible to confirm that the eucalypt is using the N. Similar cause and effect (or ‘supply and use’) questions also remain for soil pH and available phosphorus changes with increasing acacia in treatment. This study also demonstrates the difficulty in monitoring changes in soil properties over long cycles of forest plantations.The photosynthetic response to light was assessed in the stratified canopy of the mixed species field trial of the eucalypt: acacia experiment, and among commonly planted taxa of E. pellita in glasshouse pot trials. In the field trial photosynthetic capacity of fully5 expanded sun and shade leaves of both species was measured. E. pellita has a wide natural distribution with considerable variation in morphology and growth within the species, with several provenances commonly planted in north Queensland. Photosynthetic capacity and leaf nutrient content of three of these taxa (two from northern occurrences and one from southern occurrences of E. pellita) were measured on two occasions in glasshouse pot trials. A non rectangular hyperbolic function was used to describe the light response curves, and analysis of variance was used to determine differences in the biologically relevant curve parameters between treatments. In the field trial sun and shade leaves of E. pellita produced similar light saturated photosynthetic rates, and experienced little competition for light from the acacia crowns. In contrast there was significant variation in the photosynthetic response between acacia sun and shade leaves. In the glasshouse trials, differences in leaf and petiole morphology were observed, which were coupled with differences in leaf nutrient content and highly significant variation in light saturated photosynthetic rate between the three taxa. This study characterised the light response of E. pellita and suggests that differences in physiological responses to resource availability should be expected among taxa within this species, which may be important for forest productivity models which endeavour to predict tree growth and resource use.An empirical model of growth of E. pellita from a designed monocultures vs. mixedspecies experiment has been used to explore system behaviour rather than predict production of this species from specific forests. This approach has allowed examination of the effect of plantation design on competition, soil nutrient pool change with time and physiological responses to light; leading to a greater understanding of why mixtures can lead to greater productivity than monocultures.
34

Growth of eucalyptus pellita in mixed species and monoculture plantations

Bristow, Mila Unknown Date (has links)
Eucalyptus pellita is a commercially important plantation hardwood species for the humid tropics of north Queensland. This species is favoured by both small-scale growers for use in mixed species woodlots targeting low-volume high-value sawn timber, and also by industrial forest companies growing monocultures for integrated pulp – sawn timber regimes. This study investigated whether mixed-species designs can increase the growth of this tropical eucalypt when compared to monocultures.A replacement series experiment with monocultures of Eucalyptus pellita (E) and Acacia peregrina (A) and mixtures in various proportions (75E:25A, 50E:50A, 25E:75A) was used to examine questions about growth and productivity. The trial was located on the Atherton Tablelands of north Queensland, Australia. High mortality in the establishment phase due to repeated damage by tropical cyclones altered the trial design. Effects of experimental designs on tree growth were estimated using a linear mixed effects model with restricted maximum likelihood analysis (REML). Volume growth of individual eucalypt trees were positively affected by the presence of acacia trees at age five years and this effect generally increased with time up to age 10 years. However, the stand volume and basal area increased with increasing proportions of E. pellita, due to its larger individual tree size. Conventional analysis did not offer convincing support for mixed-species designs. Preliminary individual-based modelling using a modified Hegyi competition index offered a solution and an equation that indicates acacias have positive ecological interactions (facilitation or competitive reduction), and definitely do not cause competition like E. pellita. These results suggest that significantly increased growth rates could be achieved with mixed-species designs over E. pellita monocultures. This statistical methodology could enable a better 4 understanding of species interactions in similarly altered experiments, or undesigned mixed-species plantations.The effects of trees on soils are highly variable and highly site and species specific. That trees can change soil chemistry over time is well established. The soil chemical properties under the eucalypt: acacia experiment were compared to several potential baseline data sources: the reference description of this soil type; those measured at 7 months after planting; and with those of soils under two adjacent vegetation types (forest and pasture) when the experiment was aged 9 years. At 9 years after planting soil total nitrogen increased with increasing proportion of acacias in the treatment. The mean total N under the acacia monoculture was significantly higher (P = 0.041) than that of either the eucalypt monoculture, or the surrounding pasture. The proportion of acacia in the treatment was positively linearly correlated with soil total N (r2 = 0.46; P = 0.018). Soils under the eucalypt monocultures were more similar to those under pasture for a range of soil chemical properties, compared with soils under treatments containing acacias. Results from this site show that the two species alter the soil chemistry in different ways. It is possible that the increased total N under the acacias could be facilitating the growth of the E. pellita, however without n-fixation analysis or tissue sampling it is not possible to confirm that the eucalypt is using the N. Similar cause and effect (or ‘supply and use’) questions also remain for soil pH and available phosphorus changes with increasing acacia in treatment. This study also demonstrates the difficulty in monitoring changes in soil properties over long cycles of forest plantations.The photosynthetic response to light was assessed in the stratified canopy of the mixed species field trial of the eucalypt: acacia experiment, and among commonly planted taxa of E. pellita in glasshouse pot trials. In the field trial photosynthetic capacity of fully5 expanded sun and shade leaves of both species was measured. E. pellita has a wide natural distribution with considerable variation in morphology and growth within the species, with several provenances commonly planted in north Queensland. Photosynthetic capacity and leaf nutrient content of three of these taxa (two from northern occurrences and one from southern occurrences of E. pellita) were measured on two occasions in glasshouse pot trials. A non rectangular hyperbolic function was used to describe the light response curves, and analysis of variance was used to determine differences in the biologically relevant curve parameters between treatments. In the field trial sun and shade leaves of E. pellita produced similar light saturated photosynthetic rates, and experienced little competition for light from the acacia crowns. In contrast there was significant variation in the photosynthetic response between acacia sun and shade leaves. In the glasshouse trials, differences in leaf and petiole morphology were observed, which were coupled with differences in leaf nutrient content and highly significant variation in light saturated photosynthetic rate between the three taxa. This study characterised the light response of E. pellita and suggests that differences in physiological responses to resource availability should be expected among taxa within this species, which may be important for forest productivity models which endeavour to predict tree growth and resource use.An empirical model of growth of E. pellita from a designed monocultures vs. mixedspecies experiment has been used to explore system behaviour rather than predict production of this species from specific forests. This approach has allowed examination of the effect of plantation design on competition, soil nutrient pool change with time and physiological responses to light; leading to a greater understanding of why mixtures can lead to greater productivity than monocultures.
35

Remote Sensing of Sagebrush Community Structural Patterns Across Scales

Langs, Lisa A. 01 May 2004 (has links)
Throughout the Intermountain West there has been a substantial reduction in both the quantity and quality of sagebrush ecosystems. To ass ist current range management objectives, numerous efforts have been made to classify and map sagebrush communities using remotely sensed data. However, the amount of deta il provided by these broad-scale mapping projects is often limited. This research evaluated the ability of a suite of airborne and satellite imagery to detect sagebrush community structural attributes, specifically percent canopy cover, live cover, density, size-vigor, and spatial arrangement of shrubs. Field data was collected at Camp Williams National Guard Training Facility near Bluffdale, Utah, within a Wyoming big sagebrush community. High-resolution color infrared (CIR) aerial photography, panchromatic, and multi-spectral satellite imagery, including data from Orb image, IKO OS, and Landsat ETM+, were used. Comparisons were made based on the inherent spatial and spectral properties of each image. In addition to the traditional pixel-based method for classifying imagery, a relatively new object-oriented approach to measure sagebrush cover was also explored. Results indicate that the quantification of sagebrush cover can be done fairly accurately in mid-level canopy cover areas regardless of the imagery used. Confidence in the cover estimates did diminish slightly in areas where sagebrush cover was relatively sparse or extremely dense. Not all structural variables were quantifiable using the coarser imagery, due to constraints of spat ial resolution. In these instances the 0.3-meter CIR imagery was exemplified. The object-oriented approach enabled an automatic delineation of the range of variability within sagebrush stands and provided an interesting alternative to measuring sagebrush community structural attributes when compared with the more traditional pixel-based approach. This research was intended to provide a resource for anyone working wi thin sagebrush ecosystems, including rangeland managers, wildlife biologists, or other remote sensors, specifically when decisions related to the appropriate selection of remotely sensed data for some intended management application is necessary. The evaluation of wildlife habitat for sagebrush-obligate species, the direction of fire management strategies and restoration efforts, and the ident ification of appropriate grazing areas are only a few of the potential applications of this work
36

Seeds in the Forest Floor of the Ponderosa Pine Type

Krygier, James T. 01 May 1955 (has links)
Regeneration of forest stands is often complicated by the establishment and competition of brush on logged and burned-over areas. The encroachment of brush in the ponderosa pine type of Idaho, particularly Ceanothus velutinus, Dougl. presents a difficult problem to the forest manager. The brush competition severely reduces the growth rate of associated trees, thus extending the period necessary to grow a crop of trees. This situation may seriously limit the economic production of a wood crop of ponderosa pine. Any approach to the solution of brush problems should include a thorough understanding of brush ecology. Those phases of ecology dealing with reproduction and distribution of brush need special emphasis. It has been assumed that most of the brush on logged or burned-over areas originated from seed stored in the forest floor; yet little is known of the quantity or distribution of these seeds. This study was carried out to learn what kind, number and variability of seed is present in the forest floor, and to investigate the number of seed located in different forest conditions, aspects and soil layers. To achieve the above objectives, 48 square-foot, duff-soil samples were taken in the ponderosa pine type of the Boise Basin Experimental Forest in Idaho. Seeds were separated from the samples and major species identified, pretreated and germinated. Appropriate statistical techniques were employed to determine significant results among the different forest conditions, aspects and soil layers sampled.
37

Bark Beetle-Induced Changes to Crown Fuel Flammability and Crown Fire Potential

Page, Wesley G 01 May 2014 (has links)
Recent outbreaks of mountain pine beetle (Dendroctonus ponderosae Hopkins) in lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests and spruce beetle (Dendroctonus rufipennis Kirby) in Engelmann spruce (Picea engelmannii Parry ex Engelm.) forests have affected vast areas across western North America. The highlevels of tree mortality associated with these outbreaks have raised concerns amongst fire managers and wildland firefighters about the effects of the tree mortality on fire behavior, particularly crown fire behavior, as crown fires hinder the ability of firefighters to conduct safe and effective fire suppression operations. Current information regarding crown fire dynamics in recently attacked forests is limited to results obtained from simulations employing either inappropriate and/or unvalidated fire behavior models based on inadequate descriptions of crown fuel flammability. The purpose of this research was to measure and characterize the changes in crown fuel flammability caused y recent bark beetle attack and to describe the implications of these changes on crown fire potential in affected forests. Results indicated that bark beetle attack causes a significant decline in moisture content and change in chemical composition in lodgepole pine and Engelmann spruce tree foliage, which substantially increases foliage flammability. Additionally, it was found that conventional models used to predict the moisture content of fine, dead surface fuels were inappropriate for predicting the moisture content of foliage on mountain pine beetle-attacked lodgepole pine trees during the red stage. Therefore, calibrated operational models and models based on diffusion theory were developed and evaluated that could accurately predict hourly fluctuations in moisture content. The implications of these changes on crown fire potential are dependent upon a host of site specific factors including outbreak duration, severity, and the specific stand characteristics. Based on our results, we believe that current fire behavior models, including popular semi-empirical and physics-based models, are currently inadequate for accurately predicting crown fire potential in forests recently attacked by bark beetles. In order to make significant progress in our understanding of crown fire potential in recently attacked forests, a substantial effort to document wildfire behavior in the field and/or to conduct experimental fires is needed.
38

Fire Frequency and the Vegetal Mosaic of the Utah State University Experimental Forest

Wadleigh-Anhold, Linda L. 01 May 1988 (has links)
A fire history study conducted for the Utah State University (USU) Experimental Forest using three distinct periods of fire frequency, historic (1700-1855), settlement (1856-1909), and suppression (1910-present), showed a decreased mean fire interval (MFI) during the settlement period and a greatly increased MFI during the suppression era. The difference was attributed to the influx of ignition sources during the settlement of the nearby Cache Valley, located 40 kilometers to the west. The interaction of settlers with the resource during logging and livestock grazing activities encouraged the high MFI and created the vegetal mosaic now observed on the study area. The elevation of the study area, 2377 m to 2651 m, places the site in the Engelmann spruce-subalpine fir zone (Picea engelmannii, Parry ex Engelm.-Abies lasiocarpa (Engelm. ex. Wats)). The suppression era and its corresponding increase in MFI has permitted the advancement of tolerant species in the understory of the intoleran lodgepole pine (Pinus contorta var. latifolia (Engelm. ex. Wats)) and aspen (Populus tremuloides Michx.). Continue suppression of disturbance from wildfire will allow the lodgepole pine cover type, which experienced the lowest MFI during the settlement period, to be further invaded by tolerant species, leading to a decrease in stand diversity and more intense fires when they do occur.
39

Ponderosa Pine Mortality and Bark Beetle-Host Dynamics Following Prescribed and Wildland Fires in the Northern Rocky Mountains, USA

Davis, Ryan Stephen 01 May 2008 (has links)
Ponderosa pine delayed mortality, and bark beetle attacks and emergence were monitored on 459 trees for 3 years following one prescribed fire in Idaho and one wildland fire in Montana. Resin flow volume (ml) was measured on 145 fire-injured ponderosa pine 2 and 3 years post-fire. Logistic regression was used to construct two predictive ponderosa pine mortality models, and two predictive bark beetle-attack models. Post-fire delayed tree mortality was greater with the presence of primary bark beetles independent of diameter at breast height (DBH) (cm), and was greater in smaller diameter trees most likely due to direct effects of fire-caused injuries; mortality was lower in trees with less percent bud kill (PBK). The frequency of bark beetle attack was greater in trees with less percent bud kill and greater bole char height proportion (CHIP). Attack frequency was also greater on trees with higher percent bud kill and greater diameter at breast height. Classification tables for all predictive models were presented for application in post-fire management development. Multivariate ANOVA analyses were used to describe the effects of morphological and fire-injury variables on ponderosa pine resin production, and bark beetle attack preference and emergence. Resin production (ml) was significantly greater on burned than unburned trees. Resin flow increased significantly between June and July 1 year following fire and from June to August 2 years following fire. Resin flow was lower on the north bole aspect than the south and west aspects of unburned trees. Resin flow of burned trees significantly increased through the summer and was greatest in trees with high pre-fire live crown length (m) (LCL). Resin flow of unburned trees differed significantly by year, month, bole aspect, and live crown length. Resin increased by month and live crown length, decreased from 2005 to 2006, and was less on the northern bole aspect than all other aspects. Bark beetles preferred to attack fire-injured trees, especially within bole-scorched areas. No significant differences in bark beetle emergence were found between fire-injured and non fire-injured trees. On burned sites, beetle emergence was greatest from larger diameter trees with less severe fire injury. Western pine beetle (Dendroctonus brevicomis LeConte) had the greatest emergence from fire-injured ponderosa pine, and Ips pini (Say) had significantly greater emergence from non fire-injured ponderosa pine.
40

Greenstrip Establishment and Management in the Intermountain West

Younkin-Kury, Brenda Kristine 01 May 2004 (has links)
Greenstrips were established at two sites in Utah to determine if seeded, grazed cool-season, perennial grasses would change fire behavior characteristics in areas currently dominated by Bromus tectorum. Frequency data were collected for both grazed and ungrazed seeded species and resident weed species. Moderate spring grazing did not negatively impact the establishment of seeded species at Camp Williams. Grazing at Promontory Point decreased Agropyron desertorum frequency and increased the frequency of Pascopyrum smithii. Biomass data collected for grazed and ungrazed treatments in both years indicated that moderate spring or winter grazing the first two years of establishment did not negatively impact seeded species. Modeled fire behavior in grazed plots indicated that fires occurring under most fire weather conditions could be managed with hand crews at Camp Williams. Simulated fire behavior at both sites indicated that management (i.e., grazing) was necessary to realize the desired fire behavior from the established greenstrips.

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