Given the long-term human habitation and prolific land use change trajectories in the eastern United States, few remnants of the pre-European settlement Mid-Atlantic forest remain on the Atlantic ...Coastal Plain. This study utilized metes and bounds witness tree locations and descriptions produced during colonial land subdivision to understand the relationships between tree types and biogeographic environments for an area on Maryland's Eastern Shore. Using correspondence analysis, we reveal habitat partitioning among witness tree species based on soil drainage characteristics, that enable the visualization of a pre-European settlement reconstructed forest. Our research finds that oak (Quercus), most often white oak (Quercus alba), was the dominant genus for most of the study area underlain by well-drained soils. To a much smaller extent, gums were also associated with these well-drained soils. Areas of poor drainage most often contained pine (Finns) and an assemblage of different oaks (Quercus spp.). Hickory (Carya), also noted in the witness tree record in small numbers, was found across all soil drainages.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Over the past ca. 350 years, anthropogenic activities on the Mid-Atlantic Coastal Plain have caused considerable soil erosion and degradation due to deforestation, intensive agriculture, and poor if ...any soil conservation practices. Early colonial descriptions indicated rich soils suitable for agriculture supported by the rapid deforestation for cultivation. Small, undisturbed family cemeteries on the Lower Eastern Shore of Maryland provided valuable markers for assessing these changes. Continued cultivation around the cemeteries has left many of them as isolated remnant knolls, elevated above the surrounding fields. Four cemetery sites were sampled in Wicomico Co., on Maryland’s Lower Eastern Shore. Topographic data for the four sites was collected using a laser-guided total station and 3-D topographic models were generated. Composite soil samples were collected from each cemetery and two locations in the adjoining field. The physical and chemical properties indicated that the cemeteries were left in situ largely undisturbed by human activities for a prolonged period. The fields surrounding the cemeteries, however, exhibited 0.43 to 0.52 m of surface soil depletion, lower organic matter, soil carbon, total nitrogen, but higher level of cations such as Ca and K, the result of liming and fertilization. Our results were consistent with our hypothesis that land clearance and farming practices have considerably eroded and altered the chemistry and structure of soils on the Lower Eastern Shore of Maryland.
Multiple historic sources were used to reconstruct the forests of the Chesapeake at the time of European colonization. Early written records (1588-1699) show forests composed of hardwoods and ...conifers; the most commonly reported hardwoods are oak (100% occurrence in the texts), followed by walnut (93.3%), sassafras (86.7%), mulberry (80.0%), ash (60.0%), and chestnut (60.0%), and the most commonly reported conifers cedar (92.9%), pine (86.7%), and cypress (73.3%). It is likely that these reports focused on trees of economic value. John Smith's 1612 map of the Chesapeake shows a forest composed of ca. 50:50 ratio of hardwoods to conifers. Hardwoods could not be identified further, while conifers could be grouped into what appear to be pine, cedar, and baldcypress. Advertisements of land for sale or lease (1751-1838) show a forest primarily composed of hardwoods (86.5%), predominantly oak, with a small conifer component (13.5%). Forest cover averaged 61.5% and ranged from 19.7 to 100%. There is no relationship between percentage of forest cover and date of advertisement, indicating little change over that time frame on settled land. Advertisements of wood for sale or wanted also indicate a forest dominated by oak. Oak was the primary material for ship construction and barrel making, as well as the major fuel source. Witness tree records from the seventeenth century (the earliest reported) on Maryland's Eastern Shore show that a mature Oak-Pine forest dominated the pre-settlement forest, with white oak (Quercus alba) the most common hardwood. Currently a Pine-Oak-Maple forest dominates the landscape, with pines the dominant conifer and maple, particularly red maple (Acer rubrum), the dominant hardwood, mainly due to fire suppression in the twentieth century.
In the southern boreal forest of Québec, jack pine (Pinus banksiana Lamb.) stands occur in two habitat units, mainland and island. These two habitats have historically experienced different fire ...regimes. Infrequent lethal fires characterize the mainland, while frequent non-lethal and infrequent lethal fires characterize the islands. Previous studies have shown that highly serotinous jack pine trees tend to dominate on the mainland, while intermediate and non-serotinous trees are more abundant on the islands. A comparison of morphological characters describing tree form, cone morphology and reproductive output was made on 14 mainland and 10 island stands in an effort to determine if they exhibited variation consistent with variation in fire regime and serotiny. Generally, mean values of the morphological and reproductive characters measured did not vary between the two habitats, nor did bark allometry. Live crown height to tree height ratio, as a function of tree age, and cone number as a function of tree height varied between the habitats. Relatively old mainland trees had a shorter crown in relation to tree height than their island counterparts. Cone number increased faster with tree height for island versus mainland trees. Island trees exhibited earlier reproduction than did mainland trees: in the island habitat the percentage of cone bearing trees (55 %) in the youngest age class (<21 years) was significantly greater than in the mainland habitat (34 %). Mainland populations were fire-resilient with a high degree of serotiny. Island populations behave like fire-resistant/fire-surviving species with a low degree of serotiny and earlier reproductive investment.
Given the long-term human habitation and prolific land use change trajectories in the eastern United States, few remnants of the pre-European settlement Mid-Atlantic forest remain on the Atlantic ...Coastal Plain. This study utilized metes and bounds witness tree locations and descriptions produced during colonial land subdivision to understand the relationships between tree types and biogeographic environments for an area on Maryland's Eastern Shore. Using correspondence analysis, we reveal habitat partitioning among witness tree species based on soil drainage characteristics, that enable the visualization of a pre-European settlement reconstructed forest. Our research finds that oak (Quercus), most often white oak (Quercus alba), was the dominant genus for most of the study area underlain by well-drained soils. To a much smaller extent, gums were also associated with these well-drained soils. Areas of poor drainage most often contained pine (Finns) and an assemblage of different oaks (Quercus spp.). Hickory (Carya), also noted in the witness tree record in small numbers, was found across all soil drainages.
Celotno besedilo
Dostopno za:
BF, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Sweet sorghum (Sorghum bicolor) was tested as a potential biofuel crop in the U.S. Mid-Atlantic. All studies were conducted on private farmland in Wicomico Co., on Maryland's Eastern Shore. In total, ...twelve cultivars were tested: Dale, Della, E2324, High Kane II, Keller, KN Morris, M81E, Mennonite, Simon, Sugar Drip, Theis and Topper 76-6. Eight cultivars were grown each year, over three years, and poorly performing cultivars were replaced. The five cultivars with the highest potential as biofuel feedstocks were Dale, Della, Keller, KN Morris and M81E. Biomass ranged from 52.9 to 64.1 Mg ha−1, juice volume from 14.0 to 22.8 Mg ha−1, Brix from 13.1 to 15.1 and theoretical ethanol yield from 1000 to 1149 L ha−1. Theoretical ethanol yield was ca. ⅓ that of grain corn grown in Maryland over the study period (2776–3798 L ha−1). Of these cultivars, Della, M81E and KN Morris had the highest grain yield (1.94–2.41 Mg ha−1). Further studies should focus on increasing ethanol yield through the improvement of agronomic practices, efficient juice extraction and the use of the “whole-crop” (juice, grain and bagasse) to generate ethanol. Potential problems for growers include lodging, particularly in areas with high winds, and grain loss to birds.
•Sweet sorghum grown as potential biofuel crop in the U.S. Mid-Atlantic.•Cultivars with the highest potential as biofuel feedstocks were Dale, Della, Keller, KN Morris and M81E: theoretical ethanol yield from 1000 – 1149 L ha−1.•Of these cultivars, Della, M81E and KN Morris had the highest grain yield (1.94 – 2.41 Mg ha−1).•Potential problems include lodging and grain loss to birds.
The allometry of axis length, diameter, and taper is described for the trunk, rachis, and rachilla of nonbranching ramets of Aralia spinosa. Significant log-linear relationships were found between ...length and diameter for all axis categories, and in all cases, scaling was negatively allometric. Linear models best described the relationship between length and diameter for the rachis and rachilla, while a quadratic model best described this relationship for the trunk. During the trunk-building stage, the safety factors for trunk height were size dependent, with larger trunks exceeding their predicted critical buckling height. Taper was described by a linear relationship between diameter and position along the axis for all axis categories. All rachises and rachillas sampled exhibited taper along the length of the axis, however, only 51% of the trunks showed continuous taper. The trunk was less tapered than the rachis, but no differences in taper were found between the trunk and the rachilla, or the rachis and the rachilla. In unbranched ramets the large bipinnately compound leaves occur the space normally occupied by lateral branches. We suggest that the rachis and rachilla are functionally equivalent to branches. that is, acting as axes of exploration and exploitation of the environment
During the crown-building phase, the mechanical architecture of the trunk of Aralia spinosa exhibits considerable ontogenetic variation. All trunks were tapered along their length, and taper was ...dependent on both ramet size and age; older, larger trunks were more tapered than younger, smaller trunks. Trunk specific gravity, % bark, wood, and pith exhibited considerable inter- and intra-ramet variation. Specific gravity increased with both increasing ramet size and age, and declined acropetally in the majority of ramets sampled. Wood specific gravity was generally unrelated to ramet size, age, or position along the length of the trunk. Percent wood increased while % pith decreased with increasing ramet size and age. There was no relationship between % bark and either ramet size or age. Both % bark and % wood tended to decline acropetally, while % pith increased acropetally. On average, 47% of the variation in specific gravity could be attributed to % wood, while 77% could be attributed to % pith. Percent bark accounted for only 14% of the variation in specific gravity. We suggest that the relatively pithy trunk of Aralia spinosa (average range: 4-15%) allows for rapid height growth, but imposes severe constraints on crown architecture and the maximum size attainable by this species.
In this study, a search is presented for the decay Υ(1S)→γA0, A0 → cc¯, where A0 is a candidate for the CP-odd Higgs boson of the next-to-minimal supersymmetric standard model. The search is based on ...data collected with the BABAR detector at the Υ(2S) resonance. A sample of Υ(1S) mesons is selected via the decay Υ(2S) → π+π– Υ(1S). The A0 → cc¯ decay is identified through the reconstruction of hadronic D0, D+, and D*(2010)+ meson decays. No significant signal is observed. The measured 90% confidence-level upper limits on the product branching fraction B(Υ(1S) → γA0)×B(A0 → cc¯) range from 7.4×10–5 to 2.4×10–3 for A0 masses from 4.00 to 8.95 GeV/c2 and 9.10 to 9.25 GeV/c2, where the region between 8.95 and 9.10 GeV/c2 is excluded because of background from Υ(2S) → γχbJ(1P), χbJ(1P) → γΥ(1S) decays.
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