I am a Professor in the Department of Forestry and Environmental Resources and associate faculty with the NC State Toxicology Program. I collaborate with diverse academic researchers as well as municipalities, state agencies, federal agencies, and landowners across disciplines of forestry, environmental chemistry, water, contaminant remediation, and community engagement. My interests include the protection of surface waters and groundwater quality and their sustainable use, ensuring forest landscapes for the future, and supporting diversity and inclusion in forestry, environmental technology, and toxicology.
SHORT DESCRIPTION OF INTERESTS:
I am interested to collaborate at the intersections of forest systems and water quality and quantity. Recent and current research focuses on short-rotation hardwood forestry, organic contaminant forecasting for groundwater and surface water, sustainable water reuse for agriculture, managing excess water from catastrophic storms, and community engagement.
- Vulnerability of wells in unconfined and confined aquifers to modern contamination from flood events , SCIENCE OF THE TOTAL ENVIRONMENT (2023)
- Non-target and suspect-screening analyses of hydroponic soybeans and passive samplers exposed to different watershed irrigation sources , SCIENCE OF THE TOTAL ENVIRONMENT (2022)
- Extreme Flooding and Nitrogen Dynamics of a Blackwater River , WATER RESOURCES RESEARCH (2021)
- Productivity and Profitability of Poplars on Fertile and Marginal Sandy Soils under Different Density and Fertilization Treatments , FORESTS (2021)
- Suspect-screening analysis of a coastal watershed before and after Hurricane Florence using high-resolution mass spectrometry , SCIENCE OF THE TOTAL ENVIRONMENT (2021)
- Matching site-suitable poplars to rotation length for optimized productivity , Forest Ecology and Management (2020)
- Water balance of municipal wastewater irrigation in a coastal forested watershed , ECOHYDROLOGY (2020)
- Adaptability of Populus to Physiography and Growing Conditions in the Southeastern USA , Forests (2019)
- Ecosystem services of poplar at long‐term phytoremediation sites in the Midwest and Southeast, United States , Wiley Interdisciplinary Reviews: Energy and Environment (2019)
- Expanding phytoremediation to the realms of known and unknown organic chemicals of concern , International Journal of Phytoremediation (2019)
Greenhouse, field, and AI optimization of germplasm for poplar and hemp are needed to address economic and environmental challenges to sustainable bioeconomies in the South's highland or mountain regions.
The US South has 245 million acres of forestland covering 46% of total land use. This region is the largest wood basket in the world where 60% of US timber derives largely from managed softwood plantations and hardwood forests. These forest systems are major economic engines to rural economies. However, nationwide, forest resources has the lowest minority representation within Food, Agricultural, Natural Resources, and Human Sciences and even lower representation in the US South. Diversity enrollment and matriculation have failed due to poor intersections of academic support, peer community support, mentoring, leadership development, and ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œreadinessÃƒÂ¢Ã¢â€šÂ¬Ã‚Â work skills. This NNF program builds on a pilot program to pipeline minority undergraduates from HBCUs to successful graduate training in forest resources at NC State University (NCSU). The proposed program recruits HBCU undergraduates and offers pre-admission mentoring and professional development for a MasterÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s of Forestry at NCSU. Our NNF program will recruit and retain four, high-caliber minority forestry graduate students and prepare them for matriculation and professional success through NNF-specific programmatic, curricular, and industry experiences in forest resources. Key NNF program elements are a minority Mentoring/Leadership Community (MLC), certified forest curriculum, and industry internships in the automation, economics, biotechnology, and science communication of forest resources. The NNF cohort will mentor minority undergraduates, disseminate their experiences, network with professionals, and participate in annual NNF program performance assessment to support pipeline sustainability. This project supports USDAÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s goal to develop a diverse and highly-skilled workforce for employment shortages in forest resources.
In North Carolina, poultry is the top agricultural industry with an economic impact of more than $37 billion, employing over 146,000 people. Although, the main heating fuel for poultry houses is propane, recent pilot studies in the state have shown that wood pellets may be a cheaper heating fuel. Anecdotal evidence also suggests that wood pellet-heated poultry houses also produce better chicken survival, health, and growth. Our goal is to comprehensively assess the technical and economic feasibility of producing pellets specifically for the poultry industry in the Western NC, where a great proportion of broiler and ÃƒÂ¢Ã¢â€šÂ¬Ã‹Å“backyardÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢ poultry farms are located. As the economics of poultry farming is heavily dependent on mortality and overall growth/productivity of chicken, we will examine how wood pellet-based heating affects indoor air quality and health of the broiler chickens in the poultry houses. Our project results will demonstrate if this fuel is cost-effective and sustainable for poultry production to facilitate decision-making about poultry house fuel selection. Additionally, our project will generate information about potential income enhancements associated with pellet-based poultry heating.
World energy demand has been continuously increasing, with no indication of slowing down in the coming years. There exists an imperative need for cleaner, sustainable, renewable energy sources that can be locally produced. Biomass is identified as a sustainable long-term plan to reduce the dependency on imported energy and as a national security strategy, and wood pellet is identified as an important biomass product with growing demand and an established expert market mainly in Europe. Many bioenergy-focused field studies conducted by NC State University have shown the efficacy of Populus as short rotation woody crops (SRWC) when clones are matched to site conditions. The objectives of this project are to develop a novel preprocessing during pellet production, assess its effects on the technical feasibility of wood pellet production, and evaluate potential of utilizing Populus clones that are suitable and highly productive in NC for producing the next generation of solid fuels. The expected outcomes include validity of the modified production method to improve the quality of wood pellets and identification of poplar clones for producing high-quality and durable pellets.
The project will prepare a diverse group of college students and high school teachers with the knowledge and interdisciplinary tools necessary to advance the future of AmericaÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s bioenergy, bioproducts, and the bioeconomy. Distance courses will be developed and taught by faculty in the Departments of Forest Biomaterials & Environmental Resources, with guidance from the College of Education, undergraduate students are recruited from historically underserved institutions (HBCU, womenÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s college, community college), as are teachers from rural, high poverty NC high schools. Undergraduates will complete three of the five online courses in bioenergy & bioproducts, and complete an industry internship, and earn a certificate. Bioproducts and bioenergy industrial and research organization partners provide hands-on internship projects in the industry or in a research setting. Rural high school science teachers will complete three of the five online courses, earn a certificate, participate in professional development workshops, carry out lessons with their students during the school year, and conduct a career fair in bioproducts and bioenergy.
Forestry is the largest manufacturing industry in North Carolina (NC). Yet, opportunities for silviculture of hardwood plantations in western NC, where hardwood sawtimber industries are primarily located, have been missing. From our extensive experience of growing short-rotation woody crops for bioenergy and environmental clean-up in different parts of NC, we understand the importance matching species/clones to site conditions and their establishment and management, know expected production costs and yields under various scenarios, and have observed high growth and survival rates of many Populus clones. We have been identifying poplar clones for their potential for high-value veneer production. Our goal is to study feasibility and development of Populus clones as veneer crops by establishing a Populus-veneer demonstration and research site in western NC Piedmont, develop species, clonal and silvicultural recommendations and enterprise budgets for such plantations, and examine post-coppicing potential of Populus clones for veneer-log production. We will collaborate with Columbia Forest Products to test log quality for veneer processing. A successful launching of Populus for veneer would join in existing markets without the requisite of new mills and offer landowners in the western Piedmont and mountains of NC with smaller stands/fields who tend to ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œtryÃƒÂ¢Ã¢â€šÂ¬Ã‚Â new promising crops with an opportunity to produce viable high-value hardwoods.
Producing feedstocks for bioenergy remains a national long-term priority. The congressionally-mandated Renewable Fuel Standard remains in effect and targets will increase with time. Many states have Renewable Portfolio Standards while the European Union increasingly is relying on the U.S. for feedstocks to support their energy and carbon policies. With low feedstock prices and high costs of establishment and production for purpose-grown energy crops, few landowners will engage in production until the enterprise is more profitable. We believe that using a modified short-rotation woody crops (SRWC) system, a high-value Populus veneer can be co-produced with energy feedstocks in North Carolina with little yield loss for feedstocks by growing high biomass-yield clones selected for the specific site based on our research with clones selected for veneer. Columbia Forest Products Inc. has expressed great interest in using Populus logs for veneer production following the outcome of processing Populus logs for veneer at their Old Fort facility in North Carolina. We propose to evaluate the efficacy of the hybrid feedstock/veneer SRWC system and evaluate the potential landowner incomes and investment quality using our established plantations, the enterprise budget and decision tool already developed, and the Populus productivity model (3PG) under development for North Carolina. We will screen and evaluate available clones for biomass yield and potential for veneer, determine optimum spacing and rotation regimes for the modified SRWC system to maximized economic returns and conduct investment quality analyses of such projects for North Carolina.
The poultry industry has an economic impact of over $37 billion for the state of North Carolina, creating 146,125 jobs in the state as of 2017. However, ammonia exposure from chicken waste creates a respiratory hazard to those poultry farm workers. Recent efforts by NC State Extension and farm operations partners for sustainable improvements to poultry production have involved adoption of wood pellets to fuel furnaces in hen houses. This dry heat has been shown to improve broiler chicken survival, growth, and quality. Contemporaneously, farm operators and workers have shared anecdotes of reduced odors in hen houses using dry wood pellet heat. We hypothesize that lower humidity in wood pellet-heated hen houses results in less production of ammonium aerosols and hence in lower exposures for poultry farm workers. Initial screening by Carolina Land & Lakes Resource Conservation and Development supports this hypothesis, but more work is needed to demonstrate that the dry heat produced by wood pellet combustion, compared with more humid air found during propane combustion, leads to lower ammonium exposures. We propose to compare ammonia concentrations in sets of hen houses from different poultry farms in Western North Carolina that use wood pellet or propane heat but are otherwise identical. A combination of continuous and integrated ammonia detectors will be used for this pilot study. Anticipated follow-up work includes sampling a greater suite of air pollutants, capturing greater spatial and temporal resolution within the hen houses, and including both personal and area samplers of particulate matter, ammonia, and carbon dioxide in the hen houses.
Ash (Fraxinus) tree species in North America face a significant threat from the emerald ash borer (Agrilus planipennis, EAB), an exotic beetle native to Asia that was first detected in 2002 infesting urban forests surrounding Detroit, MI. Since its accidental introduction, this invasive pest has spread to 35 states, the Canadian provinces of Ontario, Quebec, New Brunswick, Nova Scotia, and Manitoba, and killed hundreds of millions of ash trees. The first detections of EAB in North Carolina occurred in 2013 in Granville, Person, Vance, and Warren counties, and it has since spread to a number of additional counties throughout the mountains, Piedmont, and upper coastal plain where it threatens to extirpate all four ash species native to the state. Of particular concern is the loss of green ash (F. pennsylvanica) which is planted widely as a shade tree in urban and suburban areas and is an important timber species in the state. It is valued for both wood products and biomass production and is considered a premier species for dual wastewater treatment and bioenergy production systems. Classical biological control, the importation and release of natural enemies from a pestÃƒÂ¢Ã¢â€šÂ¬Ã¢â€žÂ¢s native range, is one of the primary management strategies currently utilized to combat the EAB infestation in North America. Three parasitoid species from Asia are currently released, one that targets EAB eggs and two that target EAB larvae. The larval parasitoids target specific EAB larval stages, so the proper timing of releases to coincide with appropriate larval stages is critical. Current EAB phenology is based on field studies conducted in Michigan and other nearby Midwestern states; these data are currently being utilized to time parasitoid releases throughout the infested range. However, EAB larval parasitoids have failed to establish south of the 40th parallel which suggests a phenological mismatch between the timing of parasitoid release and the presence of appropriate EAB life stages in the southern United States. This mismatch is supported the NC Forest Service and NCDA&CS field data that indicates EAB overwinters as larvae in central North Carolina while most studies in the north report EAB overwintering as prepupae. Data are lacking for the year-round phenological progression of EAB life stages in central North Carolina in order to understand the best time to release parasitoids and maximize their chance of establishment.
The Association of Public Health Laboratories and the NC Department of Health and Human Services recommend that private well users test their groundwater every five years for 53 possible organic chemicals. The selection of which chemicals to measure is often confusing and frustrating to private well users and to local health departments (LHD) who make recommendations for testing. One cannot test for all 53 analytes with just one analytical method, and this list excludes many organic chemicals pending Safe Drinking Water Act (SDWA) regulation and literally thousands of other chemicals and degradation products that could be present in the water. Hence, there is a gap in water quality information for private well users and LHD across urban and rural settings. My project is a collaborative effort with the Wake County Groundwater and Well Program, or WCGWP, (see Letter of Support) to assess the presence of thousands of organic chemicals and assist with county recommendations for groundwater quality analyses to private well users. I will use gas chromatography (GC) coupled to high resolution mass spectrometry (HRMS) as a diagnostic tool to screen private wells for thousands of regulated and non-regulated volatile and semi-volatile chemicals including solvents, pesticides, aromatic hydrocarbons, pharmaceutical and consumer product chemicals, endocrine disruptors, PCBs, and many other synthetic chemicals and their degradation products. The HRMS results will be compared to recent analyses of the same wells by WCGWP to evaluate HRMS efficacy for early detection of SDWA organic chemicals. The primary outcome of my effort is to assist WCGWP with their organic analyte selection recommendations to private well users.