OPTIMIZING POPLAR FOR SUSTAINABLE BIO-PRODUCTS IN THE MOUNTAINS OF NORTH CAROLINA

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: ACTIVE
• Funding Source: AFRI COMPETITIVE GRANT
• Reporting Frequency: Annual
• Accession No.: 1027691
• Grant No.: 2022-68016-36232
• Cumulative Award Amt.: $811,641.00
• Proposal No.: 2021-08970
• Project Start Date: Jan 1, 2022
• Project End Date: Dec 31, 2025
• Grant Year: 2022
• Program Code: [A1414]- Bioenergy Feedstock Logistics Program

Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695

Performing Department
NC State University

Non Technical Summary
Fraser fir, a short rotation wood crop, is central to rural, mountain bio-economies. Warming climate and loss of productive Fraser fir acreage to Phytophthora root rot are significant challenges to livelihoods in North Carolina (NC) and other southern Appalachian communities. Phytophthora-resistant Fraser fir or exotic alternatives, and their requisite seed nurseries, will require a decade or more of development. We propose to advance recent field observations of Populus (poplar) as a high value and flexible feedstock for Phytophthora-infested lands that are no longer viable for Fraser fir and Christmas tree economies. We recently milled 10-12 year-old poplar logs for veneer sheets with industry in NC. Eight-year old, veneer poplar genotypes are growing well on a site abandoned by Fraser fir growers. We will characterize poplar genotypes currently in genetic trials across NC for resistance to Phytophthora spp that will be collected, cultured, and speciated from impacted Fraser fir plantations. Prioritized poplar genotypes for fiber and candidate veneer genotypes will be challenged with Phytophthora spp to determine resistance or susceptibility in greenhouse trials. Resistant poplar will be planted on known PRR-infested acreage to optimize existing productivity and profitability models for mountain veneer and fiber poplar. Poplar-Phytophthora response, enterprise budgets (poplar and Fraser fir), and models will be aggregated in a publicly accessible database for research, extension, industry, and educational use. Project research will be integrated into a new course that addresses a current instructional gap in hardwood plantation silviculture to educate students about flexible feed stocks for sustainable bio-products and bio-economies.

Animal Health Component

50%

Research Effort Categories

Basic

10%

Applied

50%

Developmental

40%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
131	0670	1160	100%

Knowledge Area
131 - Alternative Uses of Land;

Subject Of Investigation
0670 - Short rotation woody crops, including holiday trees;

Field Of Science
1160 - Pathology;

Keywords

appalachia

bioeconomy

phytophthora

populus

veneer

Goals / Objectives
Our primary research goals are to develop a first-ever Phytophthora-resistant database for poplar (Populus spp), a demonstrated bioenergy and high-value hardwood veneer crop for Appalachian cultivation, and to produce a poplar and Fraser fir growth and profitability decision tool to support Christmas tree grower and landowner consideration of veneer poplar for Phytophthora-infested acreage that is no longer viable for Fraser fir cultivation.

Project Methods
Objective 1. Identify Phytophthora species on acreage with known PRR infestation and poplar trials.PI Whitehill will establish a comprehensive statewide repository of Phytophthora cultures from known PRR-infested CT farms and existing poplar trials. Symptomatic plant samples (n=100-200) will be collected from CT PRR-acreage and PRR-nursery sites across N.C. in years 1 and 2. Samples will also be collected from existing veneer poplar trials on prior CT acreage suspected of having PRR. In the lab, root samples will be frozen at -20°C until DNA extraction from plant roots using the Qiagen DNeasy® PowerSoil Kit or the Qiagen DNeasy® Plant MiniKit.Phytophthora presence or absence will be determined using a qPCR-Sanger sequencing assay systemthat is more sensitive than the current approved USDA-APHIS protocols using ELISA/qPCR of nuclear genes (ITS-Elicitin). The qPCR-Sanger method identifies Phytophthora positives to the species level. In addition, a species level detection of Phytophthora from environmental samples will be run based upon the amplification of two mitochondrial loci that have highly conserved mitochondrial gene order differences in Phytophthora. A local BLAST analysis will be conducted to confirm the identity of species present in the samples. In addition, sequence data will be run through the "Emerging Phytophthora" T bas tool to verify phylogenetic placement of the species.Pure culture isolates will be maintained on corn meal agar for characterization and preparation of select isolates for pathogenicity assays. Species not previously identified will be evaluated as potential pathogens on poplar through the completion of Koch's postulates.Objective 2. Screen Phytophthora species isolated and identified against Populus genotypes. The five or six most common and virulent PRR specieswill be used to challenge prioritized poplar germplasm. Poplar cuttings will be collected from existing NC field trials and rooted in pots for three months or until mean height is 0.5 m. Briefly, poplar cuttings will be inoculated using the rice grain method. Poplar cuttings will be initially separated into equal groups for each Phytophthora isolate tested in the initial experiment. Poplar cuttings will be inoculated by placing two grains of rice infested with the Phytophthora species/isolate of interest. Mortality will be assessed weekly for 16 weeks. Based on Phytophthora-poplar greenhouse trials, prioritized poplar germplasm will be established on known PRR-infested soils at three different locations with three poplar germplasm that failed the greenhouse challenge. Ten candidate poplar genotypes will be established in five blocks (n=5 replicates per block) at planting densities of 0.5m by 0.5m in late April to avoid significant frost-damage. Mortality and growth will be evaluated throughout the growing season. Dead, diseased, or slow-growing trees will be collected and PRR species extracted and identified. If mortality or PRR symptoms are not observed, a subset of root samples (n=5) will be randomly collected and tested for the presence/absence of PRR species.Objective 3. Develop growth and productivity models for mountain poplar and Fraser fir.A current 3-PG model for poplar and biomass/bioenergy will be calibrated and validated for mountain poplar veneer based on field data from two poplar genetic trials with variable planting densities at NCDA&CS/NC State research farms in Asheville and Laurel Springs, NC (Figure 2) 23,24. There are no growth models for Fraser fir so a 3-PG model will be developed for Fraser fir with field data from PI Whitehill. 3-PG model will be validated for the top-performing poplar genotypes (used in calibration) by comparing its predictions against independent growth/productivity data obtained from the other poplar stand. The validated 3-PG model (current and for veneer) will used to compare poplar productivity for veneer, for bioenergy/biomass, in bioenergy-veneer intercropping against Fraser fir productivity. The model will integrate PRR-resistance from this project with industry's evaluation of milled veneer genotypes, a project currently supported with NCDA&CS funding [PI-Ghezehei], that will occur in Fall 2021 when mills reopen to the public after Covid 19 restrictions.Objective 4. Estimate profitability of veneer poplar, intercropped veneer poplar with biomass/bioenergy, biomass/bioenergy poplar, and Fraser fir. Existing enterprise budgets will be adopted to Phytophthora-resistant poplars for mountain veneer poplar. The cost data collected will include use of herbicides (pre-emergent, post-emergent), pesticide, machinery and labor required for sub-soiling, disk, sprayers, mower, fertilization, liming, planting (trees, labor) and additional labor (herbicide and pesticide applications, pruning). Growth outputs of the validated 3-PG models will be used as inputs for economic assessments. Profitability of commercial scale poplar production for veneer, biomass/bioenergy, and intercropped poplar for both products will be assessed using net present value (NPV, $/ha) and internal rate of return (IRR, %). New enterprise budgets will be developed for Fraser fir with PI Whitehill to enable comparative profitability between veneer poplar and CT production with Fraser fir. PI Ghezehei will also determine profitability of hybrid poplar production (for veneer, bioenergy) and Fraser Fir in terms of equivalent annual value (EAV, $/ha), which will be calculated as a measure of annual income to be compared with annual incomes from other alternative productions in the affected mountain regions such as pasture and pumpkin production.Education. The project team will integrate the proposed research into an inter-departmental undergraduate capstone and graduate course, Managed Hardwood Plantations, Sustainable Bio-Products, and Environmental Services, to be offered each spring for the department's undergraduate and graduate students in Environmental Sciences, Forestry, Natural Resource, Fish and Wildlife Sciences, and Environmental Technology. A 4 credit-hour hybrid, or flex course, will be developed in year 1 that will meet once a week to support integrated classroom and instructional field experiences for upper-level undergraduate students (FOR 499) and graduate students (FOR 599) in Year 2 and 3. Curriculum approval will begin in year 2 after the first course offering. The hybrid course structure will position this course to maximize face to face time for active-learning and field experiences and for future adaptation as an online course for a pending distance-education online Master of Forestry program. An educational evaluator will help PIs assess the following.EO1. Assess, through embedded reflection activities, if student's understanding of 'sustainability' for bio-economies changes as they gain course knowledge and understanding.EO2. Evaluate how integration of research products into the course, such as enterprise budgets, growth and profitability models, and field-practice of hardwood establishment and management options, supports student's ability to critically assess poplar bio-products as sustainable replacements to conventional commercial products to ensure sustainable rural livelihoods.EO3. Determine how students value small, low-stake but graded assessments of course materials, assignments, readings, and activities to manage course materials, to stay current with learning and course assignments, and to accomplish stated course learning outcomes.EO4. Measure differences in student peer-assessment versus self-assessment of course capstone project using NC State THINK! Program's Intellectual Standards of Critical and Creative Thinking (https://think.dasa.ncsu.edu/intellectual-standards-of-critical-and-creative-thinking/).

Progress 01/01/24 to 12/31/24

Outputs
Target Audience:The project has directly enagaged landowners and Christmas Tree producers in Western North Carolina (WNC), mill operators for veneer production and hardwood saw timber, county extension agents for WNC, and the National Christmas Tree Association. The final target audience includes graduate students in Natural Resource Management and Forest Management. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?The project (through educational component for teaching course) enabled the research assistant professor to acquire a tenure track position at Western Caroline University in the area of WNC of the project for 2024. The project has trained a post-doc who is now an extension agent in Western NC. The project has trained a Masters graduate student in phytopthora cell culture and poplar changes. The project trained another Master's student now working in the private industry for forestry for conservation and carbon credit management. How have the results been disseminated to communities of interest?Yes. An active extension effort continues with face to face presentations, meetings with landowners, and digitial dissemination. What do you plan to do during the next reporting period to accomplish the goals?Complete year 3 growing season of poplar exposed to Phytopthora in the greenhouse and move to field evaluation. Continue with extension and scientific dissemination of findings.

Impacts
What was accomplished under these goals? The database is now in development for open access after 3 years of greenhouse studies monitoring poplar clones through two growing seasons and expanding the number of poplar clones with different cultivated Phytophthora species from field collection in Western NC.

Publications

• Type: Peer Reviewed Journal Articles Status: Accepted Year Published: 2025 Citation: Blumenfeld, S., Ghezehei, S., Whitehill, J. G. A., Nichols, E. Financial Analysis Tool (CT-FT) for Western North Carolina Christmas Tree Growers. In Press for 2025
• Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Cothran, C.S., Ghezehei, S., Whitehill, J. G. A., Nichols. 2024. Phytophthora Root Rot Research Update. Industry and Extension Research Update Meeting. Laurel Springs, NC
• Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Cothran, C.S., Ghezehei, S., Whitehill, J. G. A., Nichols. 2024.Accelerated climate change and increased spread of oomycete root rot pathogens in southern Appalachia impact Christmas tree based rural bioeconomies. International Christmas Tree Research and Extension Conference. Kerteminde, Denmark (August 14th, 2024)
• Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Cothran, C.S., Ghezehei, S., Whitehill, J. G. A., Nichols. 2024.Distribution and Diversity of Oomycete Root Pathogens of Fraser fir Christmas Trees in Western North Carolina. International Christmas Tree Research and Extension Conference. Kerteminde, Denmark (August 14th, 2024). International Christmas Tree Research and Extension Conference. Kerteminde, Denmark (August 14th, 2024)
• Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Cothran, C.S., Ghezehei, S., Whitehill, J. G. A., Nichols. 2024. Increased spread of oomycete root pathogens in southern Appalachia and impacts to rural bioeconomies. NCSU Dept. of Entomology and Plant Pathology Graduate Student Symposium. Raleigh, NC, USA (November 22nd, 2024).
• Type: Conference Papers and Presentations Status: Published Year Published: 2024 Citation: Cothran, C.S., Kolway, W., Ghezehei, S., Whitehill, J. G. A., Nichols. 2024.Distribution and Diversity of Oomycete Root Pathogens of Fraser fir Christmas Trees in Western North Carolina. Durham Museum of Life and Science, After hours: Holiday Spirits Event. Durham, NC, USA (December 5th, 2024).
• Type: Peer Reviewed Journal Articles Status: Under Review Year Published: 2025 Citation: Kolway, W., Cothran, C.S., Ghezehei, S., Nichols, E. G, Whitehill, J. G. Potential for elite veneer poplar on marginal Phytophthora spp. infected Christmas tree lands. Plant Disease.

Progress 01/01/23 to 12/31/23

Outputs
Target Audience:The project has directly enagaged landowners and Christmas Tree producers in Western North Carolina (WNC), mill operators for veneer production and hardwood saw timber, county extension agents for WNC, and the National Christmas Tree Association.The final target audience includes graduate in Natural Resource Management and Forest Management. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Continuedresearch training for undergraduates and graduate students in short-rotation silviculture, mensuration, and cell culture. The project has provided educational training to an early career researcher for sound pedagogy. How have the results been disseminated to communities of interest?WNC growers and extension agents met with project staff to beta-test the enterprise budget and improve its work flow and clarity. Project activities and results have been presented with talks and posters at WNC Christmas Tree Grower meetings in Feburary and August 2023. An extension publcation on the Christmas Tree Enterprise Budget is submitted to the Journal of Extension. What do you plan to do during the next reporting period to accomplish the goals?For 2024, the project will start development of the Poplar/Phytophthora database. A fact sheet for the Christmas Tree Enterprise Budget will be developed for Xtension release and tutorials to use the tool will be avaialble at the 2024 Christmas Tree Meetings. Project results will be presented at the Short Rotation Woody Crop National Conference in Missouri in May 2024 and IUFRO in Sweden in June 2024. More poplar clones will be screened forPhytophthora resistance for summer 2024. A manuscript on poplar resistance toPhytophthora will be submitted for the 2023 challenge trials. The project educational course will be offered again in 2024 with potential inclusion of students from sister institutions.

Impacts
What was accomplished under these goals? The post-doctoral researcher redesigned the experimental design for Phytophthora challengesto poplar clones. Fifteen poplar clones were challenged in a green house trial for 2023. Weekly height, basal diameter, and LiCor measurements were conducted and significant responses were observed and are in preparation for a manuscript. The 2023 trial will be carried over to 2024 to observe year 2 impacts to clonal growth. New poplar clones and Phytophthora species will be added for 2024. Based on 2023 results, resilient and vulnerable clones will be planted in the field in areas containing Phytophthora cinnanomi. One Master student has completed an extensive field collection of knownPhytophthora damage and isolated new cultures ofPhytophthora cinanoomi and three otherPhytophthora species. These cultures will be included in the 2024 poplar challenge trials.The second Master student has produced a more detailed and updated enterprise budget for Christmas Tree production that is available for users and in review at the Journal of Extension. Work continues on adapting an existing 3-PG productivity model for poplar in Piedmont and Coastal Plain NC to WNC mountains and developing enterprise budgets for veneer-poplar to compare to the new Christmas tree enterprosie budget so growers can compare production costs and profitability for various stakeholders. Chriistmas tree growers and extension agents in WNC used and provided comments to improve the The Christmas tree enterprise budget. The project held its first Advisory Board meeting in August 2023 in WNC and then by zoom. The next advisory board meeting is in February 2024 for board members to interact directly with graduate students and post-doctoral researchers on project objectives and accomplishments. This will be a zoom meeting with break out rooms to rotate project students to different advisory board groups. The project course was approved through the University curriculum committee and offered and taught in Fall 2023 to graduate students. The course will be offered again as a capstone course to undergraduate and to graduate students in 2024.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Blumenfeld, S., Ghezehei, S., Whitehill, J. G. A., Nichols, E. Developing an enterprise budget economic tool for Christmas tree growers. August 2023. North Carolina Christmas Tree Association Conference. Spruce Pine, NC, USA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Blumenfeld, S., Ghezehei, S., Whitehill, J. G. A., Nichols, E. Evaluating hybrid poplar as an alternative crop on Phytophthora-infested sites. February 2023. North Carolina Christmas Tree Association Conference. Boone, NC, USA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Kohlway W. H. & Whitehill, J. G. A. Christmas Tree Genetics: Research and Production in North Carolina. October 2023. CAMCORE Annual Meeting. Raleigh, NC, USA
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Kohlway, W. H., Nichols E. G., Whitehill, J. G. A. The Next Generation of Phytophthora Management. August 2023. North Carolina Christmas Tree Association Meeting. Spruce Pine, NC, USA.
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Cothron, C. P., Devihalli, A., Kohlway, W. H., Nichols, E. G., & Whitehill, J. G. A. Survey of Phytophthora Root Rot on Fraser Fir (Abies fraseri) Christmas Tree Farms in Western North Carolina. Poster Presented at North Carolina Christmas Tree Association Summer Meeting. Spruce Pine, NC, USA (August 11th, 2023).
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Cothron, C. P., Nichols, E. G., & Whitehill, J. G. A. NCSU CTG Update: A New Survey of Phytophthora Root Rot in Western North Carolina. Watauga County Christmas Tree Grower Association meeting. Boone, NC, USA (August 3rd, 2023; 15min, 40 ppl).
• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Blumenfeld, S., Ghezehei, S., Whitehill, J. G. A., Nichols, E. Evaluating the economic feasibility of hybrid poplar for veneer wood in western North Carolina. October 2023. Society of American Foresters National Convention. Sacramento, CA, USA.
• Type: Journal Articles Status: Submitted Year Published: 2024 Citation: Blumenfeld, S., Ghezehei, S., Whitehill, J. G. A., Nichols, E. Financial Analysis Tool (CT-FT) for Western North Carolina Christmas Tree Growers. Submitted Journal of Extension December 2023.
• Type: Conference Papers and Presentations Status: Other Year Published: 2023 Citation: Ghezehei, S. B., Hazel, D., Saloni, D., Richmond-Bryant, J., Whitehill, J. G. A., Kohlway, W., Blumenfeld, S., Cothron, C. & Nichols, E.G. Exploring the bioeconomy potential of Poplars (Populus) in North Carolina (& Southeastern USA). October 06, 2023. Seminar series. Department of Forestry at Mississippi State.
• Type: Conference Papers and Presentations Status: Other Year Published: 2023 Citation: Ghezehei, S. B., Hazel, D., Saloni, D., Richmond-Bryant, J., Whitehill, J. G. A., Kohlway, W., Blumenfeld, S., Cothron, C. & Nichols, E.G. The bioeconomy potential of short-rotation hardwoods in North Carolina. October 19, 2023. Seminar series. Department of Forestry and Environmental Resource at NC State University.
• Type: Conference Papers and Presentations Status: Other Year Published: 2023 Citation: Whitehill, J. G. A. Whitehill Christmas Tree Genetics Program & the NC Christmas Tree Industry. December 2023. NC State Librarians Extension Program Deep Dive Seminar Series. Raleigh, NC, USA.
• Type: Conference Papers and Presentations Status: Other Year Published: 2023 Citation: Nichols, E.A. Optimizing Poplar for Sustainable Bio-Products in the Mountains of North Carolina. 2023. A1414 Sustainable Bioeconomy through Bioproducts. National Program Leaders Meeting, USDA, Kansas City, MO. July 2023.

Progress 01/01/22 to 12/31/22

Outputs
Target Audience:The project has directly enagaged landowners and Christmas Tree producers in Western North Carolina (WNC). Other target audiences including mill operators for veneer production and hardwood sawmill operators in WNC. Additional target audiences include county extension agents for WNC and the NC Forest Service and USDA Forest Service. The final target audience includes undergraduate majors in Environmental Science, Forest Management, Natural Resource Management, and Sustainable Materials with the educational component. Changes/Problems:One major change was to bring poplar challenge trials withPhytophthora speciesto cell culture then greenhouse studies to reduce the volume ofPhytophthora species-contaminated soil generated and to better manage water needs for control poplars which did not survive a flash heat wave in August. ThePhytophthora species-poplar did survive given their biological containment that capture any irrigation water. Those poplar clones challenged withPhytophthora specieswere over-wintered in the greenhouse to monitor their leafing-out and growth for a second growing season. A trial of 3 poplar clones planted on soils contaminated withPhytophthora speciesat the NCDA Upper Mountain Research Station in Laurel Springs NC in 2021 continue to do well and grow. A poplar genetic trial of 33 clones planted on former Xmas tree hillslopes in 2014 continue to be managed for veneer log with expected harvest for veneer during the project duration. We hoped to offer the project course in Spring 2023 but course approval processes delayed the course offering untl Fall 2023. What opportunities for training and professional development has the project provided?The project has provided research training for undergraduates and graduate students in short-rotation silviculture, mensuration, and cell culture. The project has provided educational training to an early career researcher for sound pedagogy. How have the results been disseminated to communities of interest?The project has been disseminated directly to WNC producers with skills in short-rotation forestry - specifically Christmas Tree growers. The project will continue to particiipate in the twice annual meetings of Christmas Tree Growers for WNC and expand to the Society of American Foresters. The project course has been adverted to a diverse group of undergraduate majors and graduate students in Environmental Science, Sustainable Materials, Natural Resource Management, and Forest Management. What do you plan to do during the next reporting period to accomplish the goals?For 2023, the project activities will focus on additional screening of WNC soils and watersheds for cell culturing of other Phytophthora species that are found on Christmas tree farms. Cell culture propagation of poplar clones for rapid Phytophthora species resistance is underway. Enterpise budgets for Fraser Fir and poplar are in development as well as adaptation of our 3-PG productivity model for poplar veneer in WNC. A fact sheet is in preparation for Veneer Poplar for dissemination via NC State Extension.

Impacts
What was accomplished under these goals? Graduate students were hired and starated in August 2022. Between the start of the grant in Jan 2022 and August 2022, we supported undergraduate researchers to start greenhouse studies of poplar clone resistance to Phytophthora cinnanomi, the most virulent Phytophthora species to Fraser fir in Western NC. Undergraduate researchers presented their posters in December 2022. Based on results of the summer trials, the current Master student and Post-Doc onPhytophthorascreening are cultivating poplar clones for cell culture exposure to be followed by greenhouse pot studies then field trials where clones will be planted in soils known to havePhytophthora cinnanomi.The second Master student has produced a GIS database of preferential lands for poplar cultivation in three counties in WNC and proximity to mills. Work has begun on adapting an existing 3-PG productivity model for poplar in Piedmont and Coastal Plain NC to WNC mountains and developing enterprise budgets for veneer-poplar and Fraser Fir to provide comparisions of profitability for various stakeholders including county extension agents, Christmas tree producers, Appalachian State faculty, Mills, and landowners. The project goals and objectives were very well received at a Feb 2023 Christmas Tree Association Meeting. Landowner interest to plant poplar is strong given our prior success with milling veneer with Columbia Forest Products in Old Fort, NC. There is strong interest for updated enterprise budgets for Fraser fir that will help the project make better comparisions to poplar veneer. The course for undergraduate and graduate students has been developed and approved by the university curriculum committee to be taught in Fall 2023 as a senior undergraduate capstone course with a graduate section.

Publications

• Type: Conference Papers and Presentations Status: Published Year Published: 2023 Citation: Poster and Fact Sheet: Poplar-Veneer and Phytophthora Resistance in WNC. NC Christmas Tree Association Meeting, Boone, NC. Feb. 23rd and 24th, 2023.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2022 Citation: Bulluck, J., S. Ghezehei, J. Whitehill, and E. Guthrie Nichols. 2022. Hybrid Poplar Trees as a Replacement for Fraser Fir Christmas Trees in Phytophora-Infested Soil in WNC. State of North Carolina Undergraduate Research & Creativity Symposum. UNC-Wilmington, Dec. 3rd, 2022.
• Type: Conference Papers and Presentations Status: Accepted Year Published: 2022 Citation: Pacheco, E., S. Ghezehei, E. Guthrie Nichols, and J. Whitehill. 2022. Hybrid Poplar Resistance to Phytophora, a Soil Pathogen. State of North Carolina Undergraduate Research & Creativity Symposum. UNC-Wilmington, Dec. 3rd, 2022.
• Type: Other Status: Accepted Year Published: 2022 Citation: WHITEHILL J. G. A. Genetic solutions for the management of Phytophthora root rot in Fraser fir. Limbs and Needles. Spring/Summer 2022.