Thesis (M.S.)--University of Wisconsin--Madison, 1984. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 153-161).

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 76-80.

Thesis (Ph. D.)--University of Texas at Austin, 2005. / Vita. Includes bibliographical references.

Thesis (MSc)--University of Stellenbosch, 2005. / Bibliography. Also available via the Internet.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on Mar. 5, 2009). Includes bibliographical references (p. 116-120).

Field measures were combined with synthetic aperture radar (SAR) images to evaluate the use of radar for estimating temporal biomass and mapping of aquatic vegetation in the lower Amazon. A SAR-based methodology was developed for quantification of the annual net primary productivity (NPP) of aquatic vegetation. The predictable monomodal flooding cycle of the floodplain is the primary control of the growth pattern of the aquatic vegetation. The total biomass increased steadily from November to August following the hydrological cycle. However, the above water biophysical properties of the canopy remained constant all year around, except in November. By November, when the water level started to rise, new leaves and nodes were formed; the backscattering values were on average -12 and -l4dB for RADARS AT and JERS-1, respectively. By April, a full canopy was developed, remaining constant due to the high turn over rate of leaves. By August, the water level quickly receded, the senescent stage began, the plant water content decreased, and the stems bent, changing from an almost vertical orientation. From April onwards the backscattering coefficientes were on average -7 and -9.5 dB, respectively. The spatial variability of the canopy biophysical properties was detectable with radar data. Significant correlation existed between backscattering coefficients and above water dry biomass, height, and percentage of canopy cover. The logarithmic relationship between backscattering coefficients and biomass suggested that ( 1 ) at low biomass, high transmissivity of the microwave radiation through the vegetation canopy occurred and the backscattering was a result of quasi-specular reflection of both C and L bands and a minor contribution of canopy volume scattering from C band; (2) at intermediate levels of biomass, moderate changes in backscattering values occurred and the backscattering saturation point was reached at 470, 660, and 620 gm⁻², for C band, L band, and the index, respectively; and (3) at high biomass, the transmissivity of C and L band radiation was equally attenuated and backscattering approached similar values for both. The derived index [special characters omitted] combines the capabilities of both C and L bands providing an empirical model for estimating above water biomass [special characters omitted] with the highest R² (0.67), the lowest root mean square error (34%), and an intermediate saturation point. The despeckled composite SAR images (C and L bands from the same season) were classified using a region-based approach. Complementary information of the satellites yielded classification accuracy higher than 95% for vegetated areas of the floodplain. The seasonal thematic classification yielded an estimate of the length of inundation of different regions of the floodplain. Regions under flooded conditions of at least 300 days yr⁻¹ were colonized predominantly by the aquatic vegetation, Hymenachne amplexicaulis; the tree-like aquatic plant, Montrichartia arborescens; and some shrub-like trees. Secondary colonizers such as Cecropia sp., Pseudobombax munguba, and Astrycaryum jauari, which are tall well-developed flooded forest, colonized regions with inundation periods of approximately 150 days yr⁻¹. Climax forest colonized regions with inundation periods of approximately 60 days yr⁻¹. The combination of the mapped area of seasonal aquatic vegetation with the SAR derived-biomass estimation allowed the calculation of the seasonal total biomass. By November, the new generation of aquatic vegetation started to develop; total biomass in the area was O.l x lO⁻¹² g. The steady growth of vegetation yielded a total biomass of 1.5 x 10⁻¹² g in an area of 395 km² in May. From May onwards, with the water receding, some plants detached from the sediment and were carried towards the Amazon River. Consequently, by August, both area and total biomass decreased to 281km² and 5 x lO⁻¹¹g, respectively. Any estimate of total biomass had a margin of error of at least 18%. After correction for seasonal biomass loss, the estimated annual NPP was 6350gm⁻² or 4.l x l0⁻¹²g for the entire area. Despite the smaller dimensions and the C3 photosynthetic pathway of the dominant H. amplexicaulis, its estimated productivity was comparable to the values reported for the most productive aquatic vegetation of the Amazon floodplain, and other aquatic plants colonizing wetlands worldwide. The estimated NPP of the aquatic vegetation yielded a total carbon uptake of 1.9 x l0⁻¹² g C yr⁻¹. Calculations based on the estimated area of each habitat of the floodplain, and the productivity data suggested in the literature, resulted in a net carbon productivity from flooded forest, phytoplankton, and periphyton of 0.35 x l0⁻¹²gC yr⁻¹, 0.22 x l0⁻¹²g C yr⁻¹, 0.07 x 10⁻¹² g C yr⁻¹, respectively. The total combined autochthonous annual net productivity of the study area was 2.5 x 10⁻¹² g C, of which 75% was from C3 aquatic plants. This study represents the first attempt to develop a method to use SAR and field data for estimating spatial and temporal variations in biomass of aquatic vegetation from a natural floodplain. / Graduate

High fuel prices have created an economic climate in which oil and gas development is increasingly profitable, and consequently, is increasing rapidly in the United States. The development includes drilling new wells and expanding the pipeline network to deliver gas and oil. This is especially true in the northern Appalachian region where the relatively undeveloped Marcellus shale formation is located. The Marcellus formation has been called a "super giant" gas reservoir possibly containing 50 trillion cubic feet of recoverable natural gas (Harper, 2008). In Pennsylvania alone, over 375 wells targeting the Marcellus shale formation have been approved between 2003 and the end of 2007. However, environmental impacts from well pads and pipelines are relatively unknown. Sediment concentrations and yields were measured from four sections of an in-road pipeline in the Monongahela National Forest in Tucker County, West Virginia during summer and fall 2007 and spring 2008. The objectives of this study were to determine the influence of vegetation cover and precipitation characteristics on sediment concentrations in runoff and sediment yields from the in-road pipeline, and to compare sediment yields to forest roads. Poorly vegetated pipeline sections produced 30.92 kg of sediment throughout the study compared to 13.49 kg for the well vegetated sections. Despite this, percent vegetative ground cover had no statistically significantly effect on sediment concentrations or yields except during very intense storms. Several precipitation characteristics, especially intensity, played a significant role in explaining sediment yields and concentrations. Precipitation patterns changed with seasons, and therefore, sediment concentrations and yields varied significantly by season. The most intense storms occurred during the summer months, which is when most soil loss also occurred. Erosion rates from the pipeline were greater than from undisturbed or well-managed forest plots, but were less than rates reported for logging and skid roads when normalized for rainfall. The reduced erosion rates suggest that routing new pipelines along closed roads may be a good method to reduce erosion compared to clearing new pipeline rights-of-ways. To further reduce erosion potential, steps in the installation process that expose mineral soil should be timed to avoid periods of intense rainfall.

No description available.

Riparian areas connect terrestrial and aquatic environments. The objectives of this research were to compare the vegetation community composition and structure eight years after harvesting and to explore successional trends among buffer widths at year eight after disturbance and in a chronosequence. A series of small clearcuts were harvested in 1998 in a 70 year old second growth stand at the Malcolm Knapp Research Forest and 0m, 10m and 30m reserve zones were established adjacent to the streams. Each treatment was replicated 3 times and 3 unharvested streams were identified as controls. Overstory and understory vegetation was measured annually from the year of harvest. Canopy density was measured using a densiometer. For comparative purposes, four vegetation plots were added in riparian areas within an 1868 and an old-growth stand during the summer of 2006. Eight years after harvesting, understory vegetation development is affected by buffer width due to higher light levels, and species richness in the 10m and 0m buffers is higher than in the 30m buffer and control. Shrubs and deciduous trees dominate the 0m and 10m buffer treatments. Proximity to the stream does not affect the composition and abundance of species with the exception of herbs and mosses. In the 10m and 30m buffer treatments, up to 15% overstory trees were windthrown in the first 2 years after harvest producing large canopy gaps. Consequently, the understory development in the 10m and 30m buffers is more like that in the 1868 and old-growth stands than in the controls, but these treatments still lack the very large trees and microsite heterogeneity of the older stands. In the unharvested controls, self-thinning continues and there has been 30% mortality of mostly smaller trees over the past 8 years. However, overstory density remains high. The 0m buffer was quickly colonized by shrubs and ferns and within the last 2 years has become dominated by juvenile deciduous trees. Overall, the 10m buffer balances timber production with the maintenance of overstory and understory structure dynamics. The combined effect of light from the edge and partial windthrow is accelerating succession towards a more mature or ‘old-growth’ condition. / Forestry, Faculty of / Graduate