• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 220
  • 53
  • 30
  • 8
  • 8
  • 8
  • 8
  • 8
  • 8
  • 6
  • 6
  • 4
  • 2
  • 2
  • 1
  • Tagged with
  • 432
  • 432
  • 85
  • 69
  • 56
  • 54
  • 53
  • 43
  • 42
  • 41
  • 41
  • 40
  • 38
  • 36
  • 36
  • 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.
311

Södramedlemmars inställning till ersättning för kolinlagring / Attitude to carbon sequestration among members of Södra

Gunnarsson, Elin, Nyberg, Malin January 2022 (has links)
Skogens förmåga att ta upp koldioxid och lagra detta som kol innebär att den spelar en viktig roll i arbetet mot klimatförändringar. Hälften av Sveriges skog ägs av mer än 300,000 privata skogsägare. Skogsägare kan genom olika skogliga åtgärder förstärka skogens roll som kolsänka. Idagsaknas dock incitament för privata skogsägare att vidta dessaåtgärder. Syftet med denna studie var att undersöka intresset för ersättning för kolinlagring bland medlemmar i Södra Skogsägarna. Resultaten är baserade på en enkät som besvarades av 108 av Södras medlemmar. Resultatet pekar påatt respondenterna var intresserade av ersättning för kolinlagring, men att det fanns en osäkerhet i frågan. Faktorer som utbildningsnivå, storlek på fastighet och antal dagar som skogsägaren lägger ner på skogsbruket hade störst påverkan på intresset för ersättning för kolinlagring.
312

ROADS, DEFORESTATION, AND GHG EMISSIONS: THE ROLE OF FOREST GOVERNANCE AND CARBON TAX POLICY IN PARA AND MATO GROSSO, BRAZIL

Carlos Andres Fontanilla Diaz (11211147) 30 July 2021 (has links)
<p>This research explores the impact of road infrastructure on deforestation, the role of forest governance and a carbon tax/credit mechanism in mitigating the effect on land use change and subsequent GHG emissions, with application to the states of Pará and Mato Grosso in Brazil. Few studies have addressed how policies to protect forested land affect the rate of deforestation associated with road and infrastructure improvement. This research makes three main contributions to the literature of roads and deforestation: 1) the concept of cost of access to the “closest” market in terms of time (expressed in person hours per ten ton load) is introduced to reflect variations in the road network infrastructure; 2) development of empirical evidence of the role of forest governance in diminishing the rate of deforestation linked to roads, using data from Brazil; and 3) and assessment of the efficacy of a carbon tax/credit scheme for mitigating the impact of infrastructure investment on land use and resultant changes in GHG emissions. Access cost ranged between 0.01 and 3084 person hours per load, however 80 percent of the pixels measured less than 784 person hours across the three years analyzed (2003, 2013, and 2018). This measure facilitated a contrast in spatial accessibility due to road infrastructure across pixels within the same year and across years on a same pixel. The use of a fractional logit model allowed the incorporation of proportions of different land uses within a same pixel at the same resolution of other <a></a>variables not available at the same fine scale. Strong forest governance reduced up to 25% the elasticities on forest lands with respect to access cost; in other words, the impact of roads on deforestation is reduced by one fourth when forest governance is strengthened. These larger impacts occur at the frontier where most of the efforts need to be addressed. Finally, provided a shock in road infrastructure, a carbon tax/credit level of $82/tCO2e permitted to abate an additional amount of GHG emissions estimated in 244 million tons of CO2e released due to changes in carbon stocks and flow emissions from agricultural activities induced from changes in road infrastructure. More importantly, this research provided insights of a proportion of GHG emissions that could be abated at different levels of a carbon tax/credit.</p>
313

Quantifying the impact of biochar on plant productivity and changes to soil physical and chemical properties on a maize soybean rotation in the U.S.

Hottle, Ryan Darrell 01 October 2013 (has links)
No description available.
314

Soil carbon sequestration in Swedish semi-natural grasslands: An opportunity for climate mitigation and biodiversity conservation? : A literature study of soil carbon sequestration in relation to biodiversity

Hellsten, Anna-Sofia January 2022 (has links)
The urgent issue with a changing climate has shed a light on the agricultural system and related climate mitigatory opportunities. One natural climate solution that has reached a lot of attention during the later years is carbon sequestrations in soils. The pedosphere, the outermost layer of the earth, constitute a great carbon pool and does therefore possibly provide big opportunities to adjust carbon levels in the atmosphere. Several measures can be utilized to enhance carbon levels in soils but could possibly imply additional negative impacts on other sustainability aspects. One of these are biodiversity, which are a trait strongly connected to semi-natural grasslands. This study therefore presents an overview of the knowledge regarding carbon sequestration on semi-natural grasslands, framed in a Swedish context. Conflicts and synergies between the climate aspect and other values of semi-natural grasslands are here investigated. Firstly, a lack of reliable Swedish data was identified and problems with extrapolating data from international studies regarding soil carbon sequestration were pointed out, especially in the context of semi-natural grasslands and biodiversity. The report shows that Swedish semi-natural grasslands have a low level of carbon sequestration and moreover a low opportunity to act as a climate mitigator. Biodiversity is often a more prioritized factor for these lands and often interpreted as a hinder for climate mitigatory measures. There are, however, possible opportunities to improve the climatic impact these lands have, depending on several aspects, but do often require a broad system perspective. Synergies between climate and biodiversity were difficult to identify except the questioned statement that grazers possibly could enhance soil carbon sequestration and at the same time provide biodiversity benefits. Conflicts were based on difficulties in implementation of sequestration enhancing measures since they often, locally, implied impoverished biodiversity. / Klimatförändringar är ett aktuellt problem som även satt fokus på jordbrukets roll och dess möjligheter att minska dess koldioxidutsläpp och dämpa den globala uppvärmningen. En av de möjliga naturliga klimatlösningarna är att lagra kol i jorden. Pedosfären, jordskorpans yttersta skikt, är en stor kol-pool och utgör därför potentiellt en god möjlighet till att minska koldioxidhalten i atmosfären. Det finns flertalet möjligheter att öka kolinlagringen i jorden men dessa kan dock innebära negativa konsekvenser av andra hållbarhetsaspekter. En av dessa är biologisk mångfald, som är något som naturbetesmarker är starkt kopplade till. Denna studie presenterar en översikt över kolinlagring i naturbetesmarker i en svensk kontext. Konflikter och synergier mellan kolinlagring och andra värden av naturbetesmarker tas även upp. Först kan det nämnas att det finns osäkerheter i data från svenska naturbetesmarker och att data av kolinlagring från internationella studier ofta är svåra att extrapolera till svenska marker. Det fanns även få studier som behandlade både klimatperspektivet och biologisk mångfald på naturbetesmarker. Rapporten visar även att svenska naturbetesmarker har en låg nivå av kolinlagring och därmed en låg möjlighet att agera som en mildrande faktor gällande ett förändrat klimat, där en anledning är den begränsande totala ytan som finns definierad som naturbetesmark. Däremot finns det möjligheter att förändra klimatavtrycket dessa marker genererar. I en sådan ansats bör man inkludera en rad olika faktorer och använda ett brett systemperspektiv för vidare analys. Synergier är svåra att identifiera, bortsett från en ifrågasatt åsikt om att betande djur potentiellt båda kan bidra till biologisk mångfald och öka kolinlagringen på den betande marken. Konflikter utgörs ofta av svårigheten att många potentiellt kolinlagrande åtgärder hade direkt negativa konsekvenser för den biologiska mångfalden lokalt.
315

Estimation of aboveground terrestrial net primary productivity and analysis of its spatial and temporal trends in the conterminous United States from 1997 to 2007 using NASA-CASA model

Khanal, Sami 01 May 2010 (has links)
This study estimated monthly and annual Net Primary Productivity (NPP), an important indicator of carbon sequestration, in the Conterminous US from 1997 to 2007 using Carnegie-Ames-Stanford Approach. Vegetation condition, temperature, precipitation, photosynthetically active radiation and soil water holding capacity were used as model’s inputs. NPP values were lower than mean annual values during the year 2000 to 2003 which was probably due to extreme drought conditions during these years. Higher NPP per square meter was generally found in Savannah and Subtropical eco-divisions whereas Tropical/Subtropical deserts had the lowest NPP. Southeastern states had the highest NPP per square meter thus, made the highest contribution to the terrestrial carbon sequestration in US. Since the vegetation is one of the main factors in NPP and thus carbon sequestration, the results of this study could help in various environmental policy decisions on forest and cropland management at the state, EPA and federal levels.
316

LANDUSE AND SOIL ORGANIC CARBON VARIABILITY IN THE OLD WOMAN CREEK WATERSHED OF NORTH CENTRAL OHIO

Kroll, Jeffrey T. 06 December 2006 (has links)
No description available.
317

Spatiotemporal dynamics of coarse woody debris in a topographically complex, old-growth, deciduous forest

Davis, Jessica G. 26 August 2014 (has links)
No description available.
318

Exploring canopy structure and function as a potential mechanism of sustained carbon sequestration in aging forests

Fotis, Alexander T. January 2017 (has links)
No description available.
319

Soil Organic Carbon Dynamics and Tallgrass Prairie Land Management

Beniston, Joshua W. 15 December 2009 (has links)
No description available.
320

Biogeochemistry of Carbon on Disturbed Forest Landscapes

Amichev, Beyhan Y. 11 May 2007 (has links)
Carbon accreditation of forest development projects is essential for sequestering atmospheric CO2 under the provisions of the Kyoto Protocol. The carbon sequestration potential of surface coal-mined lands is not well known. The purpose of this work was to determine how to measure carbon sequestration and estimate the additional amount that could be sequestered using different reforestation methods compared to the common practice of establishing grasslands. I developed a thermal oxidation technique for differentiating sequestered soil carbon from inorganic and fossilized carbon found at high levels in mine soils along with a geospatial and statistical protocol for carbon monitoring and accounting. I used existing tree, litter, and soil carbon data for 14 mined and 8 adjacent, non-mined forests in the Midwestern and Eastern coal regions to determine, and model sequestered carbon across the spectrum of site index and stand age in pine, mixed, and hardwood forest stands. Finally, I developed the framework of a decision support system consisting of the first iteration of a dynamic model to predict carbon sequestration for a 60-year period for three forest types (white pine, hybrid poplar, and native hardwoods) at three levels of management intensity: low (weed control), medium (weed control and tillage) and high (weed control, tillage, and fertilization). On average, the highest amount of ecosystem carbon on mined land was sequestered by pine stands (148 Mg ha-1), followed by hardwood (130 Mg ha-1) and mixed stands (118 Mg ha-1). Non-mined hardwood stands contained 210 Mg C ha-1, which was about 62% higher than the average of all mined stands. After 60 years, the net carbon in ecosystem components, wood products, and landfills ranged from 20 to 235 Mg ha-1 among all scenarios. The highest net amount of carbon was estimated under mixed hardwood vegetation established by the highest intensity treatment. Under this scenario, a surface-mined land of average site quality would sequester net carbon stock at 235 Mg C ha-1, at a rate of 3.9 Mg C ha-1 yr-1, which was 100% greater than a grassland scenario. Reforestation is a logical choice for mined land reclamation if carbon sequestration is a management objective. / Ph. D.

Page generated in 0.1249 seconds