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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

Přírodovědný a historický pohled na oblast Dolního Poohří mezi Libochovicemi a Budyní nad Ohří / Natural and Historical View of the Area Dolní Poohří between Libochovice and Budyně nad Ohří

Burdová, Michaela January 2015 (has links)
Title: Natural and Historical view of the area Dolní Poohří between Libochovice and Budyně nad Ohří. Abstract: This presented thesis deals with detailed characteristics of Dolní Poohří in the area between Libochovice and Budyně nad Ohří. The theoretical part presents a general research of the area from the natural scientific and historical points of view. It outlines geological and pedological situation of the area which influences plant composition. Majority of the thesis is dedicated to the ecosystem of bottomland woods and to their historical evolution in the area of Dolní Poohří. It focuses on the flora and dendroflora of the observed locality and links them to mutual connection. It also summarizes individual local species of vegetation. This thesis also describes the history of the area and points out especially castle area Libochovice and Budyně nad Ohří from the historical point of view. It offers a brief historical overview of modifications of castle garden and park, as well as their current situation and plant composition. In the practical part, an educational tourist trail from Libochovice to Budyně nad Ohří has been designed. Route description, graphics and contents of the information panels, as well as work-lists for elementary and high school students are parts of the project design. An...
32

Evaluating Economic Impacts of Different Silvicultural Approaches in Bottomland Hardwood Forests of the Lower Mississippi Alluvial Valley (LMAV)

Nepal, Sunil 09 December 2016 (has links)
The purpose of this research was to model the growth and yield of bottomland hardwood forests of the Lower Mississippi Alluvial Valley and to explain the economic tradeoffs of even- and uneven-aged management. The US Forest Service (USFS) Forest Vegetation Simulator was used to model growth and yield for four different bottomland hardwood forest types using USFS inventory data. Even- and uneven-aged management scenarios were optimized for timber revenue maximization using the Land Expectation Value formula. Analyses suggested that growth and yield of even-aged and uneven-aged management approaches differ in terms of end products and harvesting time. The even-aged management scenarios performed better over the uneven-aged management scenarios with few exceptions; however, the magnitude of the economic tradeoff depended upon initial stand conditions and required rates of return. These analyses will allow landowners to understand how much economic gain or loss they may realize by adopting an alternative management.
33

Assessing the Early Growth Performance and Survival of Two Oak Species and Three Planting Stocks on Hurricane Katrina Damaged Land

Miles, Charles Holden 03 May 2019 (has links)
Hurricane Katrina had a devastating impact on bottomland hardwood forests in 2005 resulting in damage to nearly 1.2 billion cubic meters of timber. Following such a natural disaster, natural regeneration is typically not a viable option because the seed source has been destroyed on site. Therefore, an economically efficient method of artificial regeneration is considered the most appropriate technique for reforesting these damaged areas. However, few studies have evaluated comparative research that examined early survival and growth performance of various oak species and stock types in such planting settings. This project was implemented in an effort to expand upon what is already known from previous artificial regeneration attempts on Hurricane Katrina damaged lands. Bareroot, conventional containerized, and large potted EKOgrownTM seedlings of cherrybark oak (Quercus pagoda Raf.) and willow oak (Quercus phellos L.) were planted on two sites located in south Mississippi. Survival was assessed monthly and at the end of each growing season, whereas height and groundline diameter (GLD) were measured immediately post planting and at the end of each growing season. Analysis of variance (ANOVA) and Tukey-Kramer multiple comparisons procedure (MCP), where appropriate, were performed to determine any significant differences. After the first growing season, cherrybark oak did not exhibit a substantial difference regarding survival performance when compared to willow oak (75.5 percent and 76.5 percent, respectively). After two growing seasons, willow oak exhibited considerably greater survival (74.0 percent) overall when compared to cherrybark oak (70.5 percent). Bareroot seedlings had the highest survival (87.2 percent). Conventional containerized seedlings had unacceptable survival (47.5 percent) and EKOgrownTM seedlings had acceptable survival (82.0 percent). EKOgrownTM seedlings demonstrated the best overall GLD growth of all planting stocks (3.9 mm respectively). Bareroot seedlings had the second best overall GLD growth (1.5 mm) and conventional containerized had the least amount of overall GLD growth (0.8 mm). Overall height growth when comparing all three planting stocks bareroot, conventional containerized, and EKOgrownTM were similar to one another (-3.5cm, -0.8cm, and -3.6cm respectively). Therefore, based on an overall consideration of cost and performance, bareroot seedlings are considered the most effective option of the two species considered for artificial regeneration utilized in this study.
34

Exudation Rates and δ<sup>13</sup>C Signatures of Bottomland Tree Root Soluble Organic Carbon: Relationships to Plant and Environmental Characteristics

Gougherty, Steven W. January 2015 (has links)
No description available.
35

Vegetation dynamics and response to disturbance of floodplain forest ecosystems with a focus on lianas

Allen, Bruce Peter 06 June 2007 (has links)
No description available.
36

The influence of hydrology and time on productivity and soil development of created and restored wetlands

Anderson, Christopher John 02 December 2005 (has links)
No description available.
37

The Effects of Mechanical Site Preparation Treatment and Species Selection on Survival and Carbon Pools in 12-Year-Old American Sycamore (<i>Platanus occidentalis</i>) and Willow Oak (<i>Quercus phellos</i>) Riparian Plantations in the Southeastern U.S. Piedmont

Lynn, Drake Havelock 16 July 2024 (has links)
Riparian wetlands may provide numerous ecosystem services, including water quality protection, food and fiber supply, wildlife habitat, and carbon sequestration. In recent years, riparian forests have received increased attention and funding for riparian forest restoration projects. Unfortunately, failures of riparian restoration efforts are likely due to mortality of planted trees. Tree mortality is commonly attributable to several factors, including selection of species that are not well suited to the wetland sites, inadequate planting densities, soil compaction associated with former agricultural activities, lack of microtopographic relief that allow small seedling to survive on wet sites, competition by herbaceous plants, and browse. Selection of well-suited species, dense planting and use of mechanical soil site preparations are all potential remedies to partially address success of wetland restoration plantings. Riparian restoration projects have historically been undertaken with goals of improving water quality and/or wildlife habitat, but in recent years there has been increased valuation of carbon sequestration. Carbon valuation appears to be increasing, but more research is needed to determine rates and pools of carbon accumulation in riparian areas. Our research quantifies forest establishment effects on multiple carbon pools in a densely planted, 12-year-old old-field riparian restoration. Our research evaluated the effects of four soil mechanical site preparations (bed, disk, pit, and mound and rip) and species selection (American sycamore (Platanus occidentalis) and willow oak, (Quercus phellos) on forest establishment and carbon storage across multiple pools, namely in planted trees, herbaceous vegetation, fine roots, organic soil horizons, and the mineral soil. At 12 years, we found that species selection was more important to carbon storage than site preparation. American sycamore was well suited to the site and had better survival than willow oak (64% vs 42% survival). American sycamore also stored more carbon across all site preparations than willow oak. Measured carbon storage averaged 74.8 Mg ha-1 for American sycamore treatments and 63.1 Mg ha-1 for willow oak treatments. The plots were densely planted (1.2 m (4ft) by 1.8 m (6ft) spacing), and forests were established even in higher mortality willow oak plots. These results indicate that high planting density is potentially a viable practice for establishing riparian forest cover, especially if desired species are marginally site suited or other survival inhibiting factors exist. / Master of Science / Riparian forests located within the floodplain of streams are known to protect stream water quality, provide wildlife habitat, and store carbon. Due to these benefits, trees may be replanted on riparian areas that were formerly used for agriculture. Unfortunately, trees planted on these restoration sites have often died. The tree mortality may be due to planting incorrect tree species that may struggle on wet floodplains, soil compaction from agricultural practices, not enough trees being planted, and restored floodplains lacking small, elevated areas common across natural wetlands known to favor tree rooting and survival. Reasonably, selecting species that are well suited to a specific site, planting trees more densely, and using plowing methods designed to break up compaction and create some relief in elevation would amend these issues. Traditionally, floodplain restorations have focused on improving water quality and providing habitat for wildlife, but the benefits of storing carbon have become increasingly valuable in recent years. While we know that wetlands store carbon, research is needed to examine how quickly and where carbon is stored. Our research quantifies forest establishment and carbon storage of very densely planted, 12-year-old American sycamore (Platanus occidentalis) and willow oak (Quercus phellos) plantations. This research examines the effects four soil tillage methods and tree species selection had on tree survival and carbon storage. Carbon storage was measured in vegetation, soil, and small roots. Twelve years after planting, species selection had a greater impact on carbon storage than soil tillage methods. No tillage method altered survival or total carbon after 12 years, but American sycamore was found to have better survival and more carbon than willow oak in all soil tillage treatments. Both species were successful in establishing planted forests on the floodplain, but the success was aided by the very high initial numbers of planted trees that ensured enough trees would survive on the site even after trees were lost to mortality. Creation of willow oak forests benefitted more from dense planting, as it was less suited to the site and more planted willow oaks died. We recommend tillage for compacted soil, selecting the most suitable tree species, and planting adequate numbers of trees.

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