@article{lauren e. o'brien_urbanek_gregory_2022, title={Ecological functions and human benefits of urban forests}, volume={75}, ISSN={["1610-8167"]}, DOI={10.1016/j.ufug.2022.127707}, abstractNote={The recent sprawl of urbanization in the Eastern U.S. perpetuated by population growth and economic success has caused landscapes to become vulnerable to degradation. As urban development encroaches on such landscapes, various anthropogenic stressors are introduced including air pollution, land conversion, and alterations in watershed hydrology. Across various disciplines, urban forests have been presented as a method to ameliorate human and environmental health in metropolitan environments. Understanding how to incorporate urban forestry into city design is critical and urban planners would benefit from a review that holistically describes the diverse set of services urban forests have to offer. We conducted a review to highlight the ecological functions and human benefits of urban forests and to identify gaps in the literature. We synthesized the findings of research studies in the last 20 years to illuminate the human, abiotic, and biotic services of urban forestry. As environmental quality is rapidly deteriorating in anthropogenic environments, our findings suggest city planners should consider trees as a method of mitigation to alleviate these impacts. Ultimately, when managing urban forests, an interdisciplinary approach involving all levels of governance is necessary to ensure the maximum potential of urban trees. Through this study, the consolidated research can aid in sustainable development and innovation to combat the anthropogenic stressors associated with the sprawl of urbanization.}, journal={URBAN FORESTRY & URBAN GREENING}, author={Lauren E. O'Brien and Urbanek, Rachael E. and Gregory, James D.}, year={2022}, month={Sep} }
 @article{caldwell_vepraskas_gregory_skaggs_huffman_2011, title={Linking plant ecology and long-term hydrology to improve wetland restoration success}, volume={54}, DOI={10.13031/2013.40662}, abstractNote={Although millions of dollars are spent restoring wetlands, failures are common, in part because the planted vegetation cannot survive in the restored hydrology. Wetland restoration would be more successful if the hydrologic requirements of wetland plant communities were known so that the most appropriate plants could be selected for the range of projected hydrology at the site. Here we describe how hydrologic models can be used to characterize the long-term hydrology of wetland plant communities, and we show how these results can be used to define wetland design criteria. In our study, we quantified differences in long-term (40-year) hydrologic characteristics of the pond pine woodland (PPW), nonriverine swamp forest (NRSF), high pocosin (HP), and bay forest (BF) plant communities native to the North Carolina Coastal Plain. We found that the median water level was 8 cm below the land surface in PPW and 9, 2, and 8 cm above the land surface for NRSF, HP, and BF, respectively. When the land surface was inundated, the median duration of inundation was 91 d year-1 for PPW and 317, 243, and 307 d year-1 for NRSF, HP, and BF, respectively. Our models suggested that the PPW received an average of 15% of its water input from groundwater inflow, whereas the other communities we modeled did not appear to receive groundwater inflow. Using these results and soil organic layer thickness, we developed and propose design criteria linking soil, vegetation, and hydrology parameters that should contribute to improved restoration success.}, number={6}, journal={Transactions of the ASABE}, author={Caldwell, P. V. and Vepraskas, Michael and Gregory, J. D. and Skaggs, R. W. and Huffman, R. L.}, year={2011}, pages={2129–2137} }
 @article{elam_stucky_wentworth_gregory_2009, title={Vascular Flora, Plant Communities, and Soils of a Significant Natural Area in the Middle Atlantic Coastal Plain (Craven County, North Carolina)}, volume={74}, ISSN={["1938-4386"]}, DOI={10.2179/08-07.1}, abstractNote={Abstract Cool Springs Environmental Education Center (CSEEC), owned by Weyerhaeuser Company, includes a 591 ha State Significant Natural Area. It is located in Craven County, North Carolina, in the floristically rich Atlantic Coastal Plain. A vascular flora inventory documented the occurrences of 567 species and sub-specific taxa and 303 genera in 118 plant families, including populations of the Atlantic Coastal Plain endemics Pondspice (Litsea aestivalis) and LeBlond's Coastal Goldenrod (Solidago villosicarpa). We identified twenty plant community types, including the uncommon Longleaf Pine (Pinus palustris) Woodland, Bald Cypress–Tupelo Gum (Taxodium distichum – Nyssa aquatica) Swamp, a number of small depression wetland communities, and the novel Sand Laurel Oak-Loblolly Pine (Quercus hemisphaerica – Pinus taeda) Woodland. Soils ranged from excessively drained sands to very poorly drained organics. The order of the soil mapping units according to the number of plant taxa they supported per unit area was TaB > PO > Ln > Mu > DO, MM > Se > KuB. Among five of 12 floristic study sites having positive residuals in the regression of log species richness on log area, CSEEC had the third largest residual. There was no relationship between the residuals from regressions of log species on log area and soil drainage heterogeneity on log area. The occurrences of two rare plant species, a species-rich flora, ten natural plant community types, and an assemblage of wet and dry soils in a variety of geomorphic settings are objective factors justifying the recognition of CSEEC as a State Significant Natural Area.}, number={1}, journal={CASTANEA}, author={Elam, Caitlin E. and Stucky, Jon M. and Wentworth, Thomas R. and Gregory, James D.}, year={2009}, month={Mar}, pages={53–77} }
 @article{caldwell_vepraskas_gregory_2007, title={Physical properties of natural organic soils in Carolina Bays of the southeastern United States}, volume={71}, ISSN={["0361-5995"]}, DOI={10.2136/sssaj2006.0108}, abstractNote={Hydrologic models are useful tools for designing wetland restoration projects, but they are difficult to use for sites with natural organic soils because few soil property data are available for these soils. The objective of this study was to measure the physical properties of organic soils needed to calibrate hydrologic models of three natural Carolina Bay wetlands in the southeastern USA. Undisturbed soil cores were collected at each site for laboratory measurement of saturated hydraulic conductivity, soil water characteristic curves, bulk density, particle density, and total porosity. Field measurements of saturated hydraulic conductivity were also made. The Oi, Oe, and Oa horizons in the natural organic soils had similar bulk densities (0.16 g cm -3 ), total porosities (0.90 cm 3 cm -3 ), and particle densities (1.50 g cm -3 ). However, field-measured saturated hydraulic conductivities decreased as the level of decomposition increased, going from 45 to 7.1 to 1.5 cm h -1 for the Oi, Oe, and Oa horizons, respectively. Soil water characteristic data revealed an abundance of large pores (>0.3 mm) in the Oi horizons, which likely explains their high saturated hydraulic conductivity relative to the Oe and Oa horizons, which had fewer large pores. Using the data collected in this study, mathematical relationships were developed to predict the total porosity and the saturated hydraulic conductivity of these organic soils based on more easily obtainable data, such as bulk density and the organic horizon type.}, number={3}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Caldwell, P. V. and Vepraskas, M. J. and Gregory, J. D.}, year={2007}, pages={1051–1057} }
 @article{caldwell_vepraskas_skaggs_gregory_2007, title={Simulating the water budgets of natural Carolina bay wetlands}, volume={27}, ISSN={["0277-5212"]}, DOI={10.1672/0277-5212(2007)27[1112:stwbon]2.0.co;2}, abstractNote={Wetland restoration projects attempt to recreate the hydrology found in natural wetlands, but little is known of the water budgets associated with wetlands in their natural state. The objective of this study was to compute the water budgets of three natural Carolina bay wetlands in Bladen County, North Carolina, USA. DRAINMOD models of various locations in the bays were calibrated with measured water table depths over a 2-yr period using inputs of rainfall, air temperature, and soil physical properties. The models were successful in simulating water table depths at all well locations during the calibration period with average absolute deviations between simulated and measured water table depths of approximately 4 cm. Measured and simulated data revealed very shallow (< 0.1 m) water table depths at all of the bays. Groundwater inflow was a significant component of the water balance at locations near the perimeters of the bays, ranging from 3%–26% of the total water input for these sites during the study period. A semi-confined aquifer below one of the bays was likely the source of groundwater inflow for that bay. Meanwhile, locations near the centers of the bays did not have groundwater inflow as an input to their water budgets. Groundwater outflow for the centers of the bays ranged from 2%–21% of rainfall. Areas near the perimeters of the bays were recharge, discharge, or flow-through wetlands depending on hydrologic conditions at the sites. Areas near the centers of the bays exhibited characteristics of recharge wetlands only. These results were consistent across the three Carolina bays studied, and can be used to better understand the hydrology of natural Carolina bays, improving the success of restoration projects of similar sites.}, number={4}, journal={WETLANDS}, author={Caldwell, Peter V. and Vepraskas, Michael J. and Skaggs, R. Wayne and Gregory, James D.}, year={2007}, month={Dec}, pages={1112–1123} }
 @article{schaberg_aruna_cubbage_hess_abt_richter_warren_gregory_snider_sherling_et al._2005, title={Economic and ecological impacts of wood chip production in North Carolina: an integrated assessment and subsequent applications}, volume={7}, ISSN={["1872-7050"]}, DOI={10.1016/S1389-9341(03)00029-7}, abstractNote={The North Carolina Wood Chip Mill Study represents an integrated assessment of the economic and ecological impacts associated with production of wood chips at satellite chip mills in the state of North Carolina (NC), USA. Mandated by the Governor of NC, the study was attended by a high degree of public scrutiny. We report principal findings, and describe the processes by which we dealt with uncertainty resulting from limited data availability, methods used to foster public involvement and efforts to reconcile public concerns over forest harvests with our narrower mandate to examine chip mills. We considered the hypotheses that chip mills fostered widespread industrial clearcutting, increased utilization of previously noncommercial timber (especially small hardwoods), depleted future growing stocks of sawtimber, and might create adverse ecological consequences or impair aesthetics important to recreational forest users. NC wood-based industries are a major component of the state's economy, but lagged the state in economic growth from 1977 to 1996. Over the same period, the nature-based tourism sector grew rapidly. Forest land losses in North Carolina from 1982 to 1997 totaled more than one million acres. We used an econometric model to adjust timber land base and project timber supply dynamics to 2020. The simulation indicated that softwood removals exceeded growth from 1990 onward. Hardwood removals exceed growth by 2005, causing inventory levels to decline slightly by the end of the projection period. Wood chip mills processed approximately 27% of the state's chipwood harvest and 12% of the state's total timber harvest. They were statistically correlated with increased timber harvests in the state, especially in the Piedmont and the Mountains. Chip mills have effective storm water management plans and do not show visible signs of adversely affecting water quality. Higher levels of timber harvest alter forest structures in the Coastal Plain and Piedmont, generally creating less habitat for bird, amphibian and reptile species of conservation concern. Fewer species are adversely affected in the Mountains. Public opinion about chip mills is polarized, and controversy exists principally in the western portion of the state. Overall, public acceptance of study findings was favorable, and selected elements of the research findings have been used to support a variety of advocacy positions.}, number={2}, journal={FOREST POLICY AND ECONOMICS}, author={Schaberg, RH and Aruna, PB and Cubbage, FW and Hess, GR and Abt, RC and Richter, DD and Warren, ST and Gregory, JD and Snider, AG and Sherling, S and et al.}, year={2005}, month={Feb}, pages={157–174} }
 @article{caldwell_adams_niewoehner_vepraskas_gregory_2005, title={Sampling device to extract intact cores in saturated organic soils}, volume={69}, ISSN={["1435-0661"]}, DOI={10.2136/sssaj2005.0150}, abstractNote={Physical property data on organic soils are lacking due to difficulty in collecting undisturbed samples from these frequently saturated and weakly consolidated soils. A sampling device was constructed to extract undisturbed cores from saturated organic soils in a forested setting. The sampler consists of a 100‐cm‐long, 7.6‐cm‐diam. schedule 40 PVC pipe that was fitted with female threaded adapters on either end. A cutting head was constructed to cut through the fibric root mat and other woody debris in the profile by gluing a 7.6‐cm‐diam. hole‐saw to a male threaded adaptor that was attached to the PVC pipe. The sampler was rotated by hand into the organic soil with gentle downward pressure. When the desired depth was reached, the remaining air space in the PVC pipe was filled with water and a threaded cap was used to seal the top of the sampler. A 1.3‐cm‐diam. galvanized pipe was inserted next to the sampler to add water to the bottom of the core, relieving the suction created as the core was pulled from the soil. The sampler and vent pipe were pulled from the soil either by hand or with a tripod–winch arrangement. Before the cutting head was raised above the water table, it was removed and replaced with another threaded PVC cap. The 100‐cm‐long pipe containing the soil core was then cut into 7.6‐cm‐long sections using a wheel‐type PVC pipe cutter. Saturated hydraulic conductivity and soil water characteristics were then measured in the laboratory using the resulting 7.6‐cm‐long samples encased in the PVC cylinders.}, number={6}, journal={SOIL SCIENCE SOCIETY OF AMERICA JOURNAL}, author={Caldwell, PV and Adams, AA and Niewoehner, CP and Vepraskas, MJ and Gregory, JD}, year={2005}, pages={2071–2075} }
 @article{amatya_gregory_skaggs_2000, title={Effects of controlled drainage on storm event hydrology in a loblolly pine plantation}, volume={36}, ISSN={["1093-474X"]}, DOI={10.1111/j.1752-1688.2000.tb04258.x}, abstractNote={ABSTRACT:  A paired watershed approach was utilized to study the effects of three water management regimes on storm event hydrology in three experimental watersheds in a drained loblolly pine (Pinus taeda L.) plantation in eastern North Carolina. The regimes were: (1) conventional drainage, (2) controlled drainage (CD) to reduce outflows during spring fish recruitment, and (3) controlled drainage to reduce outflows and conserve water during the growing season. Data from two pit‐treatment years and three years of CD treatment with raised weirs at the watershed outlet are presented. CD treatment resulted in rises in water table elevations during the summer. But the rises were small and short‐lived due to increased evapotranspiration (ET) rates as compared to the spring treatment with lower ET demands. CD treatment had no effect on water tables deeper than 1.3 m. CD treatments, however, significantly (α= 0.05) reduced the stoning outflows for all events, and peak outflow rates for most of the events depending upon the outlet weir level. In some events, flows did not occur at all in watersheds with CD. When event outflows occurred, duration of the event was sharply reduced because of reduced effective ditch depth. Water table depth at the start of an event influenced the effect of CD treatment on storm event hydrology.}, number={1}, journal={JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION}, author={Amatya, DM and Gregory, JD and Skaggs, RW}, year={2000}, month={Feb}, pages={175–190} }
 @article{edwards_gregory_allen_1999, title={Seasonal sulfate deposition and export patterns for a small Appalachian watershed}, volume={110}, ISSN={["0049-6979"]}, DOI={10.1023/A:1005087421791}, number={1-2}, journal={WATER AIR AND SOIL POLLUTION}, author={Edwards, PJ and Gregory, JD and Allen, HL}, year={1999}, month={Feb}, pages={137–155} }
 @article{amatya_skaggs_gregory_1997, title={Evaluation of a watershed scale forest hydrologic model}, volume={32}, ISSN={["0378-3774"]}, DOI={10.1016/S0378-3774(96)01274-7}, abstractNote={A watershed scale hydrologic model (DRAINWAT) for drained forested lands was developed by coupling DRAINLOB, a field scale forestry version of DRAINMOD and the ditch and channel routing model section of FLD and STRM. The simulation model was tested with 5 years (1988–1992) of data collected on a 340 ha watershed located near Beaufort in eastern North Carolina. Testing of the model included comparison of observed and simulated daily, monthly, and annual outflows and hourly event hydrographs by three different evapotranspiration (ET) methods. Two of which (Teskey form and GS HR form) are based on the Penman-Monteith method and the third one on the Thornthwaite method. The average absolute deviation in observed and predicted daily outflows for a 5 year period was 0.94 mm day−1, when the Penman-Monteith methods were used to predict ET. The average absolute deviation in cumulative outflow when ET was predicted by the Thornthwaite method was, respectively, 23% and 50% higher compared with the values obtained with both forms of the Penman-Monteith method. Based on coefficient of determination (R2), coefficient of efficiency (E), and root mean square error (RMSE), Teskey and GS HR forms of the Penman-Monteith method performed better than the Thornthwaite method in predicting both daily and monthly outflows. However, the average daily deviations by all three methods were not significantly different at 5% level. Prediction errors in simulating monthly outflows were reduced compared with daily outflows. The predicted mean annual outflow volumes when the GS_HR and Thornthwaite methods were used for ET were in closest agreement with observed data. Statistics showed that errors resulting from use of the Thornthwaite method, with correction factors, were usually within acceptable limits given the large input data required by the Penman-Monteith ET methods. Model prediction of event hydrographs was satisfactory based on different statistical and graphical comparisons. Deviations in predicted and observed results are attributed to errors in both. Errors in the measured outflows occurred for some larger events due to weir submergence. Errors in the simulations resulted from errors in rainfall inputs, and from uncertainties in drainable porosity, hydraulic conductivity and estimates of ET due to a number of factors including approximations of leaf area index (LAI) and stomatal conductance parameters. The model performance as a whole was satisfactory given the complexity of the model, limitations of input data for the watershed, measurement errors in outflow and rainfall, and the fact that the model was not calibrated.}, number={3}, journal={AGRICULTURAL WATER MANAGEMENT}, author={Amatya, DM and Skaggs, RW and Gregory, JD}, year={1997}, month={Mar}, pages={239–258} }
 @article{amatya_skaggs_gregory_herrmann_1997, title={Hydrology of a drained forested Pocosin watershed}, volume={33}, ISSN={["0043-1370"]}, DOI={10.1111/j.1752-1688.1997.tb03530.x}, abstractNote={ABSTRACT:  In order to assess the effects. of silvicultural and drainage practices on water quality it is necessary to understand their impacts on hydrology. The hydrology of a 340 ha artificially drained forested watershed in eastern North Carolina was studied for a five‐year period (1988–92). Effects of soils, beds and changes in vegetation on water table depth, evapotranspiration (ET) and drainage outflows were analyzed. Total annual outflows from the watershed varied from 29 percent of the rainfall during the driest year (1990) when mostly mature trees were present to as much as 53 percent during a year of normal rainfall (1992) after about a third of the trees were harvested. Annual ET from the watershed, calculated as the difference between annual rainfall and outflow, varied from 76 percent of the calculated potential ET for a dry year to as much as 99 percent for a wet year. Average estimated ET was 58 percent of rainfall for the five‐year period. Flow rates per unit area were consistently higher from a smaller harvested block (Block B ‐ 82 ha) of the watershed than from the watershed as a whole. This is likely due to time lags, as drainage water flows through the ditch‐canal network in the watershed, and to timber harvesting of the smaller gaged block.}, number={3}, journal={JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION}, author={Amatya, DM and Skaggs, RW and Gregory, JD and Herrmann, RB}, year={1997}, month={Jun}, pages={535–546} }