The Appalachian region in the eastern United Sates is home to the Earth's most extensive temperate deciduous forests, but coal mining has caused forest loss and fragmentation. More than 6000 km in Appalachia have been mined for coal since 1980 under the Surface Mining Control and Reclamation Act (SMCRA). We assessed Appalachian areas mined under SMCRA for forest restoration potentials. Our objectives were to characterize soils and vegetation, to compare soil properties with those of pre-SMCRA mined lands that were reforested successfully, and to determine the effects of site age on measured properties. Soils were sampled and dominant vegetation characterized at up to 10 points on each of 25 post-SMCRA mines. Herbaceous species were dominant on 56%, native trees on 24%, and invasive exotics on 16% of assessed areas. Mean values for soil pH (5.8), electrical conductivity (0.07 dS m(-1)), base saturation (89%), and coarse fragment content (50% by mass) were not significantly different from measured levels on the pre-SMCRA forested sites, but silt+clay soil fraction (61%) was higher, bicarbonate-extractable P (4 mg kg(-1)) was lower, and bulk density (1.20 g cm(-1)) was more variable and often unfavorable. Pedogenic N and bicarbonate-extractable P in surface soils increased with site age and with the presence of weathered rocks among coarse fragments. Our results indicate a potential for many of these soils to support productive forest vegetation if replanted and if cultural practices, including temporary control of existing vegetation, soil density mitigation, and fertilization, are applied to mitigate limitations and aid forest tree reestablishment and growth.
Our goal was to determine the effects of surface mining on forest land productivity in the eastern coalfields of the USA before the passage of the Surface Mining Control and Reclamation Act of 1977 (SMCRA), and to determine the extent to which selected mine soil properties influenced forest productivity. The site productivity of 14 mined and eight nonmined sites in the eastern and midwestern coalfields were compared. Results show that site productivity of nonmined sites and 12 of the 14 mined sites was similar. Sites with low productivity were shallow, had high coarse fragment contents, and had lower fertility. Regression analysis identified five influential soil properties affecting site quality, which included soil profile base saturation (BS), total coarse fragments, total available water, C horizon total porosity, and soil profile electrical conductivity (EC). These five properties explained 52% of the variation in tree growth. Forests on most prelaw mined sites were just as productive as the forests on unmined adjacent sites and can be used as a benchmark to assess the impacts of current reclamation on mine soil quality and forest productivity.
The purpose of this study was to investigate the effects of mining practices used prior to the passage of the 1977 Surface Mining Control and Reclamation Act (SMCRA) on forest productivity and commercial value of reclaimed forest sites. Forest productivity and value of 14 mined and 8 nonmined sites throughout the eastern and midwestern coalfield regions were compared. Forest productivity of pre-SMCRA mined sites was equal to or greater than that of nonmined forests, ranging between 3.3 m3ha-1yr-1 and 12.1 m3ha-1yr-1. Management activities such as planting pine and valuable hardwood species increased the stumpage value of forests on reclaimed mine sites. Rotation-age stumpage values on mined study sites ranged between $3,064 ha-1 and $19,528 ha-1 and were commonly greater than stumpage values on nonmined reference sites. Current law requires that mined land be restored to capability levels found prior to mining. These results should provide a benchmark for reforestation success, potential forest productivity, and timber value for current reclamation activities.
Scanning electrical mobility spectrometers (SEMS) are commonly used for near real-time ultrafine particle size distribution measurements. Analysis of SEMS measurements to calculate particle size distributions requires detailed understanding of instrument characteristics and operation. Varying instrument designs are used in the different commercial SEMS systems, and data analysis with these instruments requires accurate knowledge of their relative performance. In this study, an experimental approach to evaluate and reconcile differences between different SEMS instruments is established. This approach is used to characterize the relative performance of two SEMS systems-TSI's SMPS 3936-L22 and MSP's WPS XP1000-for particle sizes in the range of 20 to 300 nm. In these tests, the instruments were operated under a low flowrate condition with aerosol and sheath air flows of 0.3 and 3 LPM, respectively. Measurements show that the particle sizing characteristics of the instruments are very consistent with each other over the entire range of particle sizes studied. Particle number characteristics are dependent on the treatment of particle losses in the system and accounting of non-idealities of transfer function. The number concentrations reported by two instruments are generally consistent with each other and with an upstream reference counter for particle sizes larger than ∼90 nm. For smaller particles, the low flowrate operation of the two systems results in significant penetration losses. A net particle detection efficiency (NPDE) factor for the two systems was determined from experiments with monodisperse aerosol. This factor is seen to be effective in characterizing and reconciling measurements made with these two SEMS instruments.
Reforestation of mined land has the potential to sequester large amounts of atmospheric carbon on sites where carbon-based fuels were extracted. The extent to which reforested mined land captures atmospheric carbon compared to natural undisturbed land is still largely unknown. We compared the amount of carbon sequestered on 14 pre-SMCRA reforested mined sites to 8 adjacent natural sites in the midwestern and eastern coalfields. Rates of carbon sequestration ranged from 0.7 to 6.7 Mg ha-1 yr-1 , depending on mine soil quality. After 20 to 55 yr, total site carbon levels on mined study sites averaged 161 (± 24) Mg ha-1 (hardwood stands) and 148 (± 41) Mg ha-1 (pine stands), while total carbon amounts on natural sites averaged 207 (± 36) Mg ha-1. The amount of carbon captured across mined sites was largely a function of forest stand age and forest and site productivity, quantitatively expressed as site index (SI) of white oak at base age 50 years. Ecosystem carbon prediction models on natural and mined sites were generated for a wide spectrum of SI and age, including carbon sequestered in tree biomass, litter layer, and soil. The natural sites' multivariate regression model (P=0.002) explained about 68% of the total variation among natural sites and the mined sites' model (P=0.064) explained 28% of the total variation in measured carbon among mined sites. This study showed that current reclamation procedures and techniques restore carbon sequestration potential on low quality sites, but carbon sequestration potential is degraded on medium to high quality sites. Better reclamation techniques are needed to ensure long-term restoration of the potential of forests and forest soil systems to sequester carbon at pre-mining levels for the entire spectrum of SI and stand age.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.