Lower Coastal Plain Research Articles

Tree Nutrition and Forest Fertilization of Pine Plantations in the Southern United States

Abstract The growth of many pine plantations in the southern United States is limited by soil nutrient availability. Therefore, forest fertilization is a common silvicultural practice throughout the South. Approximately 1.2 million ac of pine plantations were fertilized in 2004. In the last 10 years, considerable advances have been made in identifying the ecophysiological basis for stand growth and the response to fertilizer additions. Nitrogen (N) and phosphorus (P) are the nutrients that most commonly limit growth of southern pine. On wet clay soils in the lower Coastal Plain and on some well-drained soil in the upper Coastal Plain, severe P deficiencies exist. On these soils, P fertilization with 25–50 lb of P per acre at the time of planting produces a large and sustained growth response, on the order of 50 ft3 ac−1 yr−1 (1.5 tn ac−1 yr−1) throughout the rotation. On most other soils in the South, chronic deficiencies of both N and P exist. On these sites, soil nutrient availability often is adequate early in the rotation when tree demand is small. However, around the time of crown closure, N and P frequently become limiting. Fertilization with both N and P in these intermediate aged stands typically increases growth for 8–10 years. The growth response to a combination of 25 lb of P per acre plus 200 lb of N per acre averages around 55 ft3 ac−1 yr−1 (1.6 tn ac−1 yr−1) for an 8-year period. The amount of leaf area in the stand is the main factor determining the current growth rate of the stand and the potential growth response after fertilization. When stand leaf area index is less than 3.5, light capture by the stand is restricted and growth is negatively affected. In many of these stands, fertilization will increase leaf area because of increased soil nutrient availability and thus increase growth. The financial return after fertilization depends on the growth response that occurs, the cost of the fertilizer treatment, and the stumpage value of the timber produced. Using a growth response of 55 ft3 ac−1 yr−1 over 8 years, a fertilizer cost of $90 ac−1, and stumpage values from the first quarter of 2006, the internal rate of return from midrotation fertilization of a loblolly pine plantation with N and P would be approximately 16%.

Horizontal and vertical variation of 2004 Indian tsunami deposits: An example of two transects along the western coast of Thailand

We investigated horizontal and vertical variations in modern tsunami deposits along two transects at Nam Khem and Khao Lak, western coast of Thailand, deposited by the large tsunami associated with the earthquake (magnitude 9.0) of 26 December 2004 off Sumatra, Indonesia. Tsunami waves 6–10 m high struck the area approximately 2 h after the earthquake. Tsunami deposits cover the low-lying coastal plains and extend more than 1 km inland from the shoreline. No landward decrease in sediment thicknesses was found clearly at either transect. Terrace scarps and a steep slope behind the coastal plain probably stopped tsunami deposition further inland, causing substantial sediments to be deposited in front of these features. Very clear vertical variations in grain size and multiple layers are found in the deposits to about 600 m inland at Nam Khem. Fine-grained sediments overlie the coarse-grained sediments of the basal layer of the tsunami deposits. At some sites, the fine-grained sediments are overlain by another layer of coarse-grained sediments, suggesting deposits laid down in succession by multiple waves. The basal coarse-grained sediments at Nam Khem fine landward. The up-flow waned inland based on the assumption that the grain size of the basal deposits relates to the strength of the up-flow. These results are potentially useful in disaster prevention and coastal environmental change management as well as for interpreting paleotsunami deposits in geological records.

A Comparison of Planted Loblolly Pine (Pinus taeda) Growth in Areas Receiving Different Levels of Establishment Regime Intensity

Management intensity of southeastern US pine (Pinus spp.) plantations has increased during past decades, emphasizing timber production. Managers need more information about tree growth responses to different establishment intensities to successfully meet their economic and ecological objectives. We established a comparison of five loblolly pine (P. taeda) plantation establishment regimes in the Mississippi Lower Coastal Plain (LCP, n = 4), using a gradient of mechanical and chemical site preparation and herbaceous weed control intensities. Treatments varied from “low intensity” to “high intensity” and were expected to produce a gradient in vegetative and pine growth response. We monitored herbaceous and woody ground cover, woody stem density, pine survival, and pine growth during years one and two post-treatment (2002 and 2003). Herbaceous cover, woody cover, and woody stem density decreased as treatment intensity increased. Pine survival was less on Treatment 5 and decreased slightly on all treatments during 2003. Pine height and diameter increased as treatment intensity increased, except for the treatment with no mechanical preparation, indicating the importance of subsoiling and bedding in the LCP. After two growing seasons, a combination of mechanical and chemical site preparation followed by one or two years of broadcast herbaceous weed control maximized pine growth.

Crustal constraints on the uplift mechanism of the Western Ghats of India

SUMMARY Over 800 receiver functions (RFs) from three broadband and five short period stations deployed in the northern segment of the Western Ghats of India, were analysed to examine the crustal constraints on the rift flank uplift mechanism of the Ghats. Estimates of Moho depths, mean shear velocities and Poisson’s ratios were determined and used as constraints to model the RFs. The study reveals that the crust beneath the Ghats varies in thickness between 31 and 39 km and is neither uniformly thin nor thick as required by existing hypotheses for uplift mechanism. The Poisson’s ratio is 0.26 and the mean shear velocity is 3.65 km s −1 . The uncertainties in the estimates of the Moho depths and Poisson’s ratios are ± 2k m and±0.01, respectively. The crust beneath the Ghats is 3‐4 km thinner than that beneath the adjoining low-lying coastal plains suggesting block tectonics. Modelling the RFs using crustal constraints reveals sub-Moho low-velocity zones (LVZs) with velocity reductions of 0.5‐0.65 km s −1 which are confined to shallow depths of about 50 km beneath the Ghats. The persistent relief of the Ghats may be attributed to the buoyancy forces of the possibly rift related shallow upper mantle LVZs beneath the Ghats.

Optically stimulated luminescence dating of sublittoral and intertidal sediments from Dubai, UAE: Radioactive disequilibria in the uranium decay series

Shallow marine and intertidal shell rich sediments from the low coastal plain of Dubai were dated by optically stimulated luminescence. Combined high-resolution gamma spectrometry and ICP–MS analyses revealed significant disequilibria in the 238U decay series. Time dependent dose rates were modelled for two scenarios including a closed system and an open system with linear U and Ra uptake. OSL ages that were calculated using the linear uptake model are in good agreement with archaeological evidence and radiocarbon datings on shells and wood. The presented results illustrate that luminescence-dating techniques are suitable to set up a chronostratigraphic frame for calcareous coastal environments if an appropriate model is applied to consider the influence of radioactive disequilibria and time dependent dose rates. A comprehensive radionuclide analysis of the sediments is thought necessary to perform geochemically supported dose rate simulations.

Timing of Chopper Herbicide Site Preparation on Bedded Sites

Abstract Vegetation control after different application timings of Chopper herbicide (active ingredient imazapyr) relative to bedding was examined at four lower Coastal Plain study locations. Two bedding regimes, midseason and late-season, were examined at each location. Midseason bedding occurred between May and July and late-season bedding occurred between September and November. Results indicate that many of the historical application timing limitations placed on imazapyr are not necessary. Chopper herbicide in combination with methylated seed oil can be applied as early as February and as late as November, up to the day before bedding and immediately after bedding. Seasonal timing of application also was found to have a major impact on pine growth. For those treatments that provided good vegetation control, earlier season treatments resulted in the best pine growth. Optimal application timings were (1) June through September at least 3 weeks after midseason bedding, (2) February to the day before midseason bedding, and (3) February through July followed by late-season bedding. An exception is that if deciduous woody species such as hardwood or blackberry are targeted, early season applications (February–April) should not occur until these species have leafed out. The optimal timing windows are wide, allowing forest managers plenty of flexibility in scheduling operations. Use of optimal timing windows has the potential to substantially increase productivity without increasing costs.

Aspects of the hydro-geomorphology of Illawarra streams: implications for planning and design of urbanising landscapes

Streams in the Illawarra region of New South Wales have dynamic hydro-geomorphic characteristics that are atypical of the broader Sydney Basin. These characteristics include: small, steep catchments subject to intense rainfall events that are capable of generating flood discharges comparable to world maximum rainfall-runoff events; high energy escarpment channels that debouch bedload sediment fans and bars onto a low energy coastal plain; well developed macro-channels that convey high magnitude flows through the middle catchment zone; rapid and prolific vegetation growth and downstream decreasing channel capacities within the lower catchment depositional zone. This paper outlines local examples of the dynamic interactions between flood hydrology, hydraulics and geomorphology of Illawarra streams. Appropriate planning to account for their dynamic nature is particularly important in the context of catchment management for Lake Illawarra as some 10,000 - 20,000 new dwellings are planned for future development in areas currently dominated by rural land uses.

Sea‐level changes, river activity, soil development and glaciation around the western margins of the southern North Sea Basin during the Early and early Middle Pleistocene: evidence from Pakefield, Suffolk, UK

AbstractThis paper outlines evidence from Pakefield (northern Suffolk), eastern England, for sea‐level changes, river activity, soil development and glaciation during the late Early and early Middle Pleistocene (MIS 20–12) within the western margins of the southern North Sea Basin. During this time period, the area consisted of a low‐lying coastal plain and a shallow offshore shelf. The area was drained by major river systems including the Thames and Bytham. Changes in sea‐level caused several major transgressive–regressive cycles across this low‐relief region, and these changes are identified by the stratigraphic relationship between shallow marine (Wroxham Crag Formation), fluvial (Cromer Forest‐bed and Bytham formations) and glacial (Happisburgh and Lowestoft formations) sediments. Two separate glaciations are recognised—the Happisburgh (MIS 16) and Anglian (MIS 12) glaciations, and these are separated by a high sea level represented by a new member of the Wroxham Crag Formation, and several phases of river aggradation and incision. The principal driving mechanism behind sea‐level changes and river terrace development within the region during this time period is solar insolation operating over 100‐kyr eccentricity cycles. This effect is achieved by the impact of cold climate processes upon coastal, river and glacial systems and these climatically forced processes obscure the neotectonic drivers that operated over this period of time. © British Geological Survey/Natural Environment Research Council copyright 2005. Reproduced with the permission of BGS/NERC. Published by John Wiley & Sons, Ltd.

Saltwater Intrusion and Morphological Change at the Mouth of the East Alligator River, Northern Territory

Abstract Morphological changes associated with saltwater intrusion of a small salt-affected floodplain in the vicinity of the mouth of the East Alligator River were examined through interpretation of aerial photography and ground surveys. The floodplain, in the Alligator Rivers Region of the Northern Territory, Australia, includes mudflats, tidal creeks, upper and lower floodplains, and a freshwater basin impounded by cheniers. Significant morphological change has occurred since 1950, with the tidal creek extending 4 km inland. By 2000, bare saline mudflats on the coastal plain had undergone a ninefold increase, and 64% of Melaleuca spp. forest had been lost. Saltwater intrusion and associated morphological change over time appears to have been driven by drier-than-average monsoonal conditions, low-frequency and low-intensity cyclonic events, and above-average ocean water levels experienced since 1950 and particularly since the mid-1980s. Loss of vegetation on the lower coastal plain was facilitated by ex...

Fluvial systems variations in the Rio Leona Formation: Tectonic and eustatic controls on the Oligocene evolution of the Austral (Magallanes) Basin, southernmost Argentina

The stratigraphy and sedimentology of the Oligocene Río Leona Formation (Austral/Magallanes Basin) is described and interpreted on the basis of a study of two sections located in the area close to Viedma and Argentino Lakes in southern Argentina. This nonmarine unit unconformably rests on top of the marine Eocene Man Aike Formation and is transitionally covered by the shallow marine, latest Oligocene–Early Miocene Centinela Formation. The Río Leona Formation is composed of varying percentages of conglomerates, sandstones, and mudstones, as well as thin but conspicuous levels of carbonaceous shales and volcaniclastic beds. The rocks represent sedimentation in different fluvial systems. Sedimentological data indicate a progressive change in the fluvial styles from high-energy braided systems to low-energy meandering and anastomosed systems. The landscape is envisaged to have evolved during the Oligocene from a high gradient piedmont area to a low-lying coastal plain. The Patagonian Sea flooded the area by the end of the Oligocene (22–25 My). Within the framework of the nonmarine sequence stratigraphic scheme for foreland basins, the Río Leona Formation deposits represent good examples of degradational, transitional, and aggradational systems tracks. The development of a basal unconformity and the erosion of the Eocene rocks suggest an initial uplift of the source area to the west. Changes in the fluvial systems indicate an increase of the accommodation space. The Oligocene evolution of this part of the Austral Basin probably reflects a combination of tectonic processes and eustatic sea-level changes. The former may be related to an episode of uplift in the southern Andes, followed by a period of tectonic quiescence and active volcanism with strong subsidence typical of foreland basin evolution. The latter may be linked to late Paleogene glaciation–deglaciation events in Antarctica.

Flora and Soils of Wells Savannah, an Example of a Unique Savanna Type

Wells Savannah is a unique wet pine savanna located in the Lower Coastal Plain of North Carolina. It consists of two utility rights-of-way and a fire-suppressed pond pine (Pinus serotina) woodland. The objectives of this study of Wells Savannah were to characterize its soils, inventory its vascular flora, and compare its soils and flora with those of reference sites. Soil drainage, texture, and redoximorphic features were described at all locations. Wetland indices were calculated to represent the degree to which the plant communities were adapted to wet substrates. We identified 209 species in 107 genera and 48 families at Wells Savannah. Eight community associations were recognized. Wetland indices for Wells Savannah were significantly lower than those for the reference savannas. The unique combination of fine textured, very wet soil and plant species composition present at Wells Savannah has not been identified in previous studies of savannas in the region.

A Comparison of 30-yr Climatic Temperature Normals for the Southeastern United States

Thirty-year climatic normals are an integral part of climate and climate assessment, but they are typically not used to address issues of climatic change. For 104 stations within the southeastern United States, I analyze spatial parameters of the two most recent 30-yr temperature normals (1961-1990, 1971-2000) to illustrate the utility of 30-yr normals for an assessment of climatic change. My comparison of the two normal periods shows that the Southeast as a whole has experienced a small (0.10�C) but significant increase in average temperature. However, of the seven physiographic provinces examined, only the lower Coastal Plain has experienced a significant increase in temperature. My analysis of urban versus rural sites produced mixed results on the potential impacts of urbanization and the associated heat island effects on the observed changes in temperature. While some long-term analyses of the thermal climate of the Southeast have shown the region to be cooling, my results suggest that the thermal climate of the southeastern United States since 1961 is stable or slightly warming.

Using a system mixed-effects modeling method to estimate tree compartment biomass for intensively managed loblolly pines?an allometric approach

Allometric relationships between total and individual tree compartment (stem, root, branch, and foliage) biomass were investigated for intensively managed loblolly pine (Pinus taeda L.) plantations in the Lower Coastal Plain and Piedmont of Georgia. It was found that the percent of stem biomass increases with age while the inverse relationship was found for foliage and branches. Cultural treatments also impacted the proportional allocation among various tree compartments. Specifically, this investigation showed that compared with unfertilized trees, annually fertilized trees in the Lower Coastal Plain had a larger proportional biomass allocation to the stem relative to root, branch, and foliage compartments. A system of related compartment biomass models was developed that reproduces observed relationships in the raw data. This system of models uses total tree biomass to obtain estimates of biomass for other tree compartments. The flexibility of the system of biomass prediction models allows users to estimate biomass for the various compartments as a function of another known compartment biomass.

Using a system mixed-effects modeling method to estimate tree compartment biomass for intensively managed loblolly pines—an allometric approach

Allometric relationships between total and individual tree compartment (stem, root, branch, and foliage) biomass were investigated for intensively managed loblolly pine ( Pinus taeda L.) plantations in the Lower Coastal Plain and Piedmont of Georgia. It was found that the percent of stem biomass increases with age while the inverse relationship was found for foliage and branches. Cultural treatments also impacted the proportional allocation among various tree compartments. Specifically, this investigation showed that compared with unfertilized trees, annually fertilized trees in the Lower Coastal Plain had a larger proportional biomass allocation to the stem relative to root, branch, and foliage compartments. A system of related compartment biomass models was developed that reproduces observed relationships in the raw data. This system of models uses total tree biomass to obtain estimates of biomass for other tree compartments. The flexibility of the system of biomass prediction models allows users to estimate biomass for the various compartments as a function of another known compartment biomass.

Cryptic species within the freshwater isopod Mesamphisopus capensis (Phreatoicidea: Amphisopodidae) in the Western Cape, South Africa: allozyme and 12S rRNA sequence data and morphometric evidence

The freshwater phreatoicidean isopod Mesamphisopus capensis has been regarded as the most widespread of the four Mesamphisopus species occurring in the Western Cape, South Africa. To determine whether this species was monotypic across its distribution over two mountainous regions, separated by a low-lying coastal plain remnant, genetic differentiation among populations from 11 localities was studied through allozyme electrophoresis of 12 loci and sequencing of a 338-bp 12S rRNA mtDNA fragment from representative individuals. Populations of the two regions were separated by a mean identity value of 0.477. Fixed allele differences at two loci distinguished these regions. Estimates of θ indicated substantial differentiation among populations across the entire sample, as well as within each of the regions. Topologies derived through parsimony and neighbour joining supported the monophyly of the two regions. On the basis of these topologies, allele frequencies and an allozyme dendrogram, five groups were identified. Discriminant function analyses, performed on body and pereopod variables independently, revealed these groups to be well differentiated with a high rate of correct a posteriori reclassification. Using genetic distance criteria these five distinct forms may be considered to be putative species. From a conservation perspective, the two regions can be seen to represent two evolutionarily significant units, while the five groups should be regarded as management units. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 81, 235–253.

A Model for Foliage and Branch Biomass Prediction for Intensively Managed Fast Growing Loblolly Pine

Abstract Prediction models of foliage and branch biomass were derived based on the foliage distribution within the crown and the pipe model theory. Resulting models were fitted to data collected from intensively managed loblolly pine (Pinus taeda L.) plantations in the Lower Coastal Plain and Piedmont of Georgia. We found that diameter outside bark at the base of the live crown, crown height, and crown length are key predictors of foliage biomass. Together they produce reliable predictions of foliage and branch biomass for stands managed under a wide array of silvicultural treatments. The model indicates that an annual fertilization treatment significantly increased foliage and branch biomass in the Lower Coastal Plain. However, in the Piedmont, complete control of competing vegetation significantly increased foliage and branch biomass. A significant fertilization-age interaction for foliage and branch biomass was also detected in Piedmont stands. FOR. SCI. 50(1):65–80.

Palynostratigraphy and palaeoenvironment of the Middle Jurassic Sortehat Formation (Neill Klinter Group), Jameson Land, East Greenland

The grey–black mudstones of the Sortehat Formation form part of the Middle Jurassic fill of the Jameson Land Basin in East Greenland. The formation is exposed in the southernmost part of the north–south-trending, Mesozoic rift system in East Greenland that was part of the epeiric seaway between East Greenland and Norway. Sedimentological observations of the Sortehat Formation indicate deposition in an offshore marine setting that was typically low energy and periodically oxygen-deficient but was influenced by storm currents on occasion. Detailed palynological studies of the Sortehat Formation have resulted in the definition of three palynological assemblage zones recognised at four localities, namely Enhjørningen Dal and Pelion (north Jameson Land), the type section at Sortehat (central Jameson Land) and Albuen at Neill Klinter along Hurry Inlet (south-east Jameson Land). In stratigraphic order, these zones are termed the Botryococcus Assemblage Zone, the Nannoceratopsis gracilis – Nannoceratopsis senex Assemblage Zone, and the Sentusidinium pelionense Assemblage Zone. They are recognised on the basis of the identification of approximately 110 species of palynomorphs, including 45 species of spores, 30 of pollen, 22 of dinoflagellate cysts, 10 acritarch species, two species of algae, and some fungal spores. An Aalenian – ?Early Bajocian age is suggested for the Sortehat Formation on the basis of the palynoflora. Interpretation of the palynomorph assemblages suggests that the formation accumulated in a shallow, brackish marine environment. A significant terrestrial input, including the freshwater green alga Botryococcus, is recorded in the lower part of the formation and interpreted as an allochthonous accumulation in an offshore marine environment related to transgression of a low-lying coastal plain. A marked shift in the palynomorph assemblage seen by diversification of marine microplankton above the base of the formation, indicates an increase in the marine signal probably related to the onset of highstand conditions following the marine transgression.

Relationship Between Foliar δ13C and Hydraulic Pathway Length in Pinus palustris

Abstract Because of the importance of hydraulic architecture in understanding physiological differences between small and large trees, we tested the hypothesis that foliar δ13C increased with aboveground flow-path length in longleaf pine (Pinus palustris Mill.) trees of varying age and size at two sites in the lower Coastal Plain. This species offered a unique opportunity to examine variability in foliar δ13C in relation to pathway length because of the open, well-mixed canopy in savanna-like stands and concentration of foliage in splayed tufts on branch ends. At both sites, models with total flow-path length (bole + branch) explained 78–81% of the variation in foliar δ13C, and a full model with separate slopes and intercepts for each tree was required. Branch flow-path length was highly correlated with foliar δ13C and the models accounted for 76–88% of the variation in foliar δ13C, and a reduced model with one slope was suitable for each site. Flow-path length was not as well correlated to foliar N concentration, specific leaf area or tuft leaf area. Greater δ13C enrichment with increasing flow-path length indicates the need for mechanistic studies to better understand the role of hydraulic resistance in controlling leaf-level physiology within the canopy and among different size longleaf pine trees.

ELEMENTAL CONCENTRATIONS IN SOILS OF SOUTH CAROLINA1

We determined the concentrations of 25 elements in soils typical of the Southeast Atlantic Coastal Plain, Piedmont, and Blue Ridge at 50 sites in South Carolina. Our purpose was to gather baseline data on the elemental content of soils for use in dealing with land application of wastes and other environmental issues involving metal content in soils. Concentrations of more than one-half of the elements were higher in the Blue Ridge and Piedmont soils than in those in the Carolina Sandhills, Upper Coastal Plain, or Lower Coastal Plain. Concentrations of Al, Ba, Be, Cd, Co, Cr, Fe, K, Li, Mn, Na, Ni, Rb, S, Sb, Sc, V, and Zn were correlated positively with clay content. Selenium and Y were correlated negatively with clay content. Several of these elements (Al, Ba, Fe, K, Mg, Mn, Ni, S, Se, V, and Zn) were correlated positively with soil pH, but correlation coefficients were generally less than for correlations with clay content. Land use, according to cropping history, was not a significant factor affecting elemental concentrations. Sites that had been cropped to cotton or pastures for long periods of time had slightly higher concentrations of As and Cu, respectively, but differences were of little consequence. Soil Ni concentrations were higher at forest sites compared with all other sites, which may have been due to more effective biogeochemical recycling at forest sites resulting in higher soil retention. We found no evidence that soil at the 0-15-cm depth was enriched with any elements. Concentrations within the 0-15-cm depth were no different than those within the 15-30-cm depth, indicating that any enrichment that may have occurred because of anthropogenic activities had become distributed throughout the 30-cm depth as a result of tillage and natural processes. The maximum value and geometric mean of Cd concentrations were considerably greater than values reported in two other surveys of U.S. soils. Some sites in all of the land resource and land use categories had concentrations of As and Cd that translated into soil loads exceeding 30% of the cumulative pollutant load limits cited in the USEPA 503 regulations.

Nitrogen mineralization dynamics following the establishment of a loblolly pine plantation

The USDA Forest Service initiated a national study in the early 1990s to examine the effects of organic matter removal, compaction, and vegetation control on tree growth and soil processes at several locations across the United States and Canada. Our study was undertaken on the Lower Coastal Plain of North Carolina installation during the second and the fifth growing seasons following loblolly pine (Pinus taeda L.) plantation establishment. We used the in situ soil core incubation method to assess net N mineralization, and collections were conducted monthly from March to December in 1993 and 1996. The largest differences in N mineralization resulted from soil type differences between blocks. Organic matter removal did not affect N mineralization in either year; however, compaction reduced N mineralization during both years. Vegetation control had a pronounced positive effect on N mineralization and was only slightly less important as compared with soil type. Mineralization rates in year 5 were 80% less than in year 2. We hypothesized that the high N mineralization rates in year 2 may be related to a decrease in the input of soluble organic C following harvest (reducing immobilization), a quick mineralization of microbial N, fluctuating soil temperature and water conditions, and fine roots and litter biomass input following harvest.