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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.
1

An investigation into the use of aerial digital photography for monitoring coastal sand dunes

Edwards, Esther January 2001 (has links)
The coastal zone is a highly dynamic entity both spatially and temporally and when shoreline changes (and in particular retreat) occur on a hmnan time-scale, measurement of the rate of change becomes a pressing issue. This dynamism presents an excellent scenario for monitoring change using remote sensing techniques, and in the case of coastal sand dunes, where the requirement is to measure small scale changes such as erosion or accretion in the region of 10 or 20 m, aerial photography is the preferred source of remotely sensed data. The rapid developments in digital camera technology and real time satellite differential Global Positioning Systems have yielded new opportunities for mapping and monitoring environmental change when used with image processing and mapping software and state-of-the-art digital photogrammetric workstations. Despite the progress in digital technologies, however, there is still considerable lack of awareness on the part of potential users, and it is in response to this that the processing chain for data collection through to orthophoto production described here has been developed. This study explores the major issues that affect quality, mission logistics and cost and will demonstrate the methodology and application of digital techniques for producing georectified imagery and contoured orthophoto maps of coastal environments. This will be achieved through a series of case studies of dynamic dune environments in south-west England and France. Digital imagery was captured using a colour infrared Aerial Digital Photographic System and ground control was collected using differential Global Positioning Systems. This study seeks to assess the application of this imagery to coastal dune monitoring, putting these new techniques within the grasp of coastal dune managers, enabling them to make use of digital imagery captured to different specifications depending on the accuracy requirement of the end product. The results indicate that this type of imagery and the techniques used can provide the dune manager with information which would otherwise be too costly or time consuming to acquire. 2D rectification of the imagery provided maps of dune retreat and accretion with errors in the region of± 1.5m, and rectification to a higher order using 3D photogrammetric correction provided 1 :5000 contoured orthophotographs with mean xy errors in the region of 2. 5 m and mean elevation errors in the region of 1.5m.
2

Watershed and Streamside Management Zone Characterization in the Allegheny Plateau of West Virginia

Sharp, Elizabeth P. 24 September 2003 (has links)
The Streamside Management Zone (SMZ) is a cornerstone of forestry Best Management Practices to protect streamwater quality from non-point source pollution resulting from silvicultural operations. However, the exact width and harvest intensity of SMZs that best protects water quality while allowing for commercially valuable timber harvesting has not been determined. The long-term objective of this study is to characterize SMZs and watersheds before and after harvest with different SMZ widths and harvesting intensities in the Allegheny Plateau of West Virginia. The objective this paper is to present the pre-harvest SMZ and watershed characterization. Each of the watershed SMZs were characterized pre-harvest in terms of vegetation, water, soil, carbon, and monetary value within SMZs to predict how silvicultural treatments will affect the future stands. The major overstory tree species found are Acer saccharum, Liriodendron tulipifera, Fagus grandifolia, Tilia americana, Betula lenta, snags, Betula lutea, Fraxinus spp., and Acer rubrum. The overall average streamwater temperature is 13°C. Highest daily temperature occurred in the mid-afternoon and lowest temperatures occurred just before sunrise. Streamwater quality was good, with near neutral pH, low nitrogen content, and high dissolved oxygen. USLE erosion estimates predicted an erosion rate of 2.9 Mg/ha/yr in the SMZ. However, the sediment rods showed an overall accumulation of soil in the SMZ, averaging 173 Mg/ha/yr. This equates to an average watershed loss of 10.9 Mg/ha/yr. In-stream and SMZ LWD volume was approximately equal at 28 and 33 m3/ha. Large woody debris was more decayed in the SMZ than in-stream LWD. / Master of Science
3

Relationships Between Streamside Management Zone Width and Biotic Communities of Headwater Streams in West Virginia

Corrao, Jason James 28 September 2005 (has links)
The importance of streamside management zones (SMZ) in minimizing the impact of non-point source pollution from silvicultural operations is recognized by the forestry Best Management Practices of most states. However, research concerning the SMZ width and harvesting intensity required to maintain water quality and biotic communities is limited. The goal of this study is to evaluate the efficacy of different SMZ widths and forest harvesting intensities within SMZs, in maintaining the water quality and biotic communities of 22 headwater streams located in the mountains of East-central West Virginia. Streams were organized in four blocks and randomly assigned one of six silvicultural treatments involving variation of SMZ width and harvesting intensity within the SMZ; 30.5 m SMZ with no residual harvest, 30.5 m SMZ with 50% residual harvest, 15.3 m SMZ with no residual harvest, 15.3 m SMZ with a 50% residual harvest, 4.5 m SMZ and control (no harvest within the watershed). Stream water chemistry parameters (in particular, NO3, NH4, Ca, Mg, conductivity and total dissolved solids) as well as aquatic macroinvertebrate communities were monitored from June 2003 through March 2005. Average nitrate concentration in streams harvested with a 4.5 m SMZ was more than 4 times as high as that of control streams. Average summer and fall stream temperatures were inversely related to SMZ width. Mean values for a number of macroinvertebrate community metrics were indicative of poorer water quality in streams harvested with a 4.5 m SMZ. During this short-term study SMZs of at least 15.3 m appeared to be sufficient to maintain water quality. However, harvesting was restricted to one side of the stream and logging induced stream disturbances were observed even with SMZs of 30.5 m. For these reasons SMZs of at least 30.5 m are recommended as a cautionary measure to minimize the potential for impacts to biotic communities. In addition, residual harvest of up to 50% of the basal area within the SMZ did not appear to impact water quality during the temporal scope of the study. / Master of Science
4

FOREST HARVEST EQUIPMENT MOVEMENT AND SEDIMENT DELIVERY TO STREAMS

Bowker, Daniel Whiteside 01 January 2013 (has links)
Streamside management zones (SMZs) have become important management techniques to prevent the introduction of sediment to stream networks. This study examined the current Kentucky best management practice (BMP) guidelines for SMZs by outfitting mobile forest harvest equipment with global positioning system (GPS) receivers, enabling modeling of equipment traffic and spatial analysis of stream sediment delivery. Three SMZ configurations were implemented during commercial timber harvest, along with four different techniques of crossing ephemeral channels, in order to determine where and why sediment was introduced to the stream network. Results indicate that increasing the SMZ buffer width leads to decreased sediment delivery, and that requiring an SMZ buffer with some canopy retention on ephemeral channels will lead to improvements in stream water quality. Care should be taken in the placement and construction of water control measures for skid trail retirement, and improved stream channel crossings such as bridges and pipe culverts should be required to improve water quality over unimproved fords. A northeasterly aspect of harvested areas was shown to be related to increased sediment delivery to streams, while surface roughness downslope from the skid trail system was shown to decrease sediment delivery.
5

EFFECTS OF STREAMSIDE MANAGEMENT ZONE TIMBER HARVEST ON SALAMANDER COMMUNITIES IN ROBINSON FOREST

Maigret, Thomas 01 January 2013 (has links)
Salamanders are critical components of forest ecosystems, in terms of total biomass, as well as for their value as indicators of ecosystem stress. Considering the worldwide decline in amphibian populations, the known effects of timber harvest on salamander populations, and the importance of the forest products industry in Kentucky and elsewhere, the impacts of silvicultural operations on salamander communities cannot be overlooked. The objective was to investigate the effects of three different silvicultural treatments, each involving different streamside management zone (SMZ) characteristics, on salamander communities in ephemeral streams. Data were collected by regular checks of pitfall traps, coverboards, and transect searches. Using both pre- and post-harvest data, abundance estimates were acquired using binomial mixture models. Declines in some species of terrestrial and stream-breeding salamanders were detected, and were shown to be likely related to characteristics of the corresponding silvicultural treatment. Applying modest SMZ regulations to ephemeral streams would likely alleviate these declines significantly.
6

Bird, Plant, and Herpetofaunal Associations in Cove Forests and Pine Plantations in Mississippi

Posner, Aaron Weston 12 May 2012 (has links)
I investigated plant and animal community characteristics on 14 forest stands in north central Mississippi. Study sites included 9 pine plantations, 3 streamside management zones, and 2 hardwood cove forests. I estimated relationships between faunal metrics and habitat characteristics. I measured vegetation characteristics within quadrant and nested plot designs to estimate understory, midstory, and overstory species composition and structure. I inventoried breeding birds using point count surveys and sampled herpetofauna diversity using area-constrained searches within belt transects during 2008 and 2009. I detected 39 species of birds in 2008, 43 species of birds in 2009, 11 species of amphibians, and 9 species of reptiles. Hardwood cove sites supported more deep forest-dwelling bird and salamander species; whereas, pine stands supported more grassland bird species. Species richness and abundance of birds was related to snag DBH. Species richness and abundance of herpetofauna was related to number of understory plant species.
7

Streamside Management Zone effectiveness for protecting water quality following forestland application of biosolids

Pratt, W. Aaron 14 August 2008 (has links)
Biosolids, materials resulting from domestic sewage treatment, are surface applied to forest soils to increase nutrient availability. Retaining streamside management zones (SMZs) can limit nutrient pollution of streams. We delineated 15 m SMZs along three intermittent streams in an 18-year-old Pinus taeda L. plantation. We applied biosolids outside the SMZ on one side of each of the streams maintaining the other side of the stream as control. We collected water samples from the three treated and six reference streams as well as from the perennial stream both upstream and downstream from the intermittent streams for 12 months following treatment. Along transects perpendicular to the treated streams, we collected overland flow samples, soil solution samples at 60 cm and extracts from ion exchange membranes (IEMs) placed in the surface soil. We found elevated nitrate concentrations outside the SMZ in the treated side soil solution samples, in which concentrations remained below 1.5 mg L-1. Nutrient concentrations outside the SMZ in treated side IEM extracts increased following biosolids application, returning to near control levels after one year. Nutrient concentrations in IEM extracts were not elevated adjacent to the streams. We observed elevated phosphorus concentrations adjacent to the stream in overland flow during one period on the treated side of the stream. Stream nutrient concentrations showed few differences downstream from the treatment with concentrations below 1.5 mg L-1. Our results indicate that a 15 m SMZ protected streams from nutrient pollution for the first year following biosolids application to adjacent forestlands. / Master of Science
8

Nutrient Movement in Streamside Management Zones and Piedmont Streams Following Forest Fertilization

Secoges, Joseph Michael 06 July 2009 (has links)
Many states' Best Management Practices (BMP) programs established Streamside Management Zone (SMZ) widths based on limited or inadequate data with regard to nutrient fluxes from silvicultural activities. Previous studies in forested watersheds have shown slight post-harvest increases of several nutrients in streams. Also, in agricultural settings, increased nitrogen (N) and phosphorous (P) levels have been detected in streams. However, little is known about the effectiveness of recommended forested SMZ widths for controlling nutrient fluxes following fertilizer application. Diammonium phosphate (DAP) and urea fertilizers were applied to subwatersheds of 2 to 3 year-old loblolly pine (Pinus taeda L.) plantations upslope from SMZ study areas throughout Buckingham Co., VA. Three replications of four SMZ treatment widths (30.5m, 15.2m, and 7.6m plus a thinned 15.2m SMZ) were studied using surface water collectors, cation/anion exchange membranes, lysimeters, and stream grab-samples. Measurement devices were spaced symmetrically across the SMZ from the uphill SMZ edge to stream edge with grab samples being collected approximately 20m upstream and 20m downstream of the fertilized area. Little nitrogen and phosphorous movement was detected in surface water which was monitored using surface water collectors. Near-surface water flow sampling using ionic exchange membranes resulted in our most complete dataset and showed infrequent lateral ion transport in the litter and upper soil layers even after water passed over an approximately 1m wide, seeded firebreak located between the SMZ dripline and fertilized area. Results from lysimeter samples used to measure subsurface flow were limited due to dry conditions; however, the limited samples indicate that only minute levels of nitrogen and phosphorous are transported laterally via shallow subsurface and surface flow. Overall, sampling indicated that only minute quantities of nitrogen and phosphorous were ever transported from the fertilized clearcut to the riparian area. Results indicate that even a 7.6m wide SMZ with a seeded firebreak is adequate to protect streams from industrial fertilizer application in a relatively dry year, but wider SMZs may be necessary for other benefits. / Master of Science
9

Effects of Green Tree Retention on Birds of Southern Pine Plantations

Parrish, Michael Clay 14 December 2018 (has links)
In the southern United States, institutional forest owners engaged in forest certification programs often retain unharvested or less-intensively harvested vegetation when clearcut harvesting intensively managed pine (Pinus spp.) forests (“IMPFs”), a practice called ‘green tree retention’. I investigated resultant patterns of land cover and retained structural elements in recently-harvested IMPF management units (“MUs”) and related them to avian biodiversity to provide information to support harvest decisions. First, to provide forest managers baseline data on retention, I screen-digitized land cover on 1187 MUs (totaling 51646 ha) and characterized green tree retention levels and internal land cover attributes (Chapter 2). I found MU land cover was dominated by regenerating clearcuts (mean: 80.5%), streamside management zones (“SMZs”; vegetated buffers surrounding intermittent and perennial streams; 14.0%) and stringers (buffers surrounding ephemeral streams; 3.3%). Next, I surveyed 60 MUs for vegetation stem density and cover (Chapter 3). Concurrently, I surveyed avian community density and richness (Chapter 4). Vegetation and avian metrics were compared and contrasted across the dominant cover types (with emphasis on stringer/SMZ similarity) to understand impacts of retained structural elements on biodiversity outcomes. I found that snag and log density, midstory pine density, understory deciduous cover, and ground cover were not different in stringers and SMZs; however, overstory (pine and deciduous) and midstory (deciduous) tree density was lower in stringers than in SMZs, and understory pine density was greater in SMZs. Species overlap between cover types was high (74% to 84%), but SMZs and stringers provided 27% of MU species richness. Stringers appeared to benefit both shrubland- and forest-associated birds. Finally, I sampled land cover across 4450 sq-km surrounding the 60 MUs, and performed ordination analyses to identify associations between local-scale (MU interiors) and landscape-scale (3-km buffers around MUs) land cover and avian guild diversity (Chapter 5). I found the region to be >90% forested. Cover type data explained 41% of the partial variation in avian density and total species richness. Local-scale MU characteristics appeared more important than landscape-scale characteristics in explaining avian biodiversity responses. My results suggest that retained structural features support and enhance MU biodiversity in harvested IMPFs.
10

ESTRATÉGIAS DE AGRICULTURA DE PRECISÃO PARA DEFINIÇÃO DE ZONAS DE MANEJO EM SISTEMAS DE INTEGRAÇÃO LAVOURA PECUÁRIA / STRATEGIES OF PRECISION AGRICULTURE FOR DEFINING MANAGEMENT ZONES CROP IN LIVESTOCK SYSTEMS

Pilon, Marcelo 05 June 2014 (has links)
The Precision Agriculture is a great tool to assist and enhance the spatial and temporal management of agricultural activities. In this sense the site-specific management, provides an understanding of agricultural crops or livestock on smaller spatial scales than those adopted in conventional agriculture. For data acquisition and obtaining maps, the Electrical Conductivity of the soil, the Penetration Resistance and Chemical Analysis of the Soil were used because they are variables which correlate with factors for grain production. This study evaluated the data obtained in a reference unit of Embrapa, submitted to a system of long-term crop-livestock integration succeeded by soybean cultivation during the summer and ryegrass pasture during the winter. The data on variability obtained on soybean yield, were used to establish management zones in pasture productivity, along with the (EC), (PR) and (CAS). From the values of correlation between soybean yield and forage production presented, it was observed that there was a positive correlation between the productivity of soybean and the forage production, only in the first cut of the forage. This result demonstrates that the response in productivity of different crops is distinct in the same area. Considering the results, it is concluded that the EC measures showed good repeatability, with a strong positive correlation with relatively small scattering. On the other hand, the areas of EC were not effective to determine the areas of management in the pasture phase, still fitting complementary studies to verify the efficiency of the EC in relation to variability in pasture productivity in southern Brazil. / A Agricultura de Precisão é uma excelente ferramenta para auxiliar e aprimorar o gerenciamento espacial e temporal das atividades agrícolas. Nesse sentido o manejo sítio-específico, proporciona o entendimento de lavouras agrícolas ou pecuárias em escalas espaciais menores do que aquelas adotadas na agricultura convencional. Para a aquisição de dados e obtenção de mapas, a Condutividade Elétrica do Solo, a Resistência a Penetração e a Análise Química do Solo, foram utilizadas por serem variáveis que se correlacionam com fatores de produção dos grãos. O presente trabalho avaliou os dados obtidos em uma unidade de referência da Embrapa, submetida a um sistema de integração lavoura-pecuária de longa duração com sucessão de cultivo de soja durante o verão e de pastagem de azevém durante o inverno. Os dados relativos à variabilidade obtida na produtividade da soja, foram utilizados para tentar estabelecer zonas de manejo na produtividade da pastagem, juntamente com a (CE), (RP) e (AQS). A partir dos valores de correlação entre a produtividade da soja e a produção de forragem apresentados, foi observado que houve correlação positiva da produtividade da soja com a produção de forragem, apenas no primeiro corte da forragem. Este resultado demonstra que a resposta em produtividade de culturas diferentes é distinta em uma mesma área. Tendo em vista os resultados obtidos, conclui-se que as medidas de (CE) apresentaram boa repetibilidade, com forte correlação positiva e com espalhamento relativamente pequeno. Por outro lado, as zonas de (CE) não foram correlacionadas para determinar as zonas de manejo na fase da pastagem, cabendo ainda estudos complementares para verificar a eficiência da (CE) em relação à variabilidade na produtividade do pasto na região sul do Brasil.

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