Charles David Ray, Ph.D.

Charles David Ray, Ph.D.

  • Associate Professor, Ecosystem Science and Management
205 Forest Resources Building
University Park, PA 16802

Areas of Expertise

  • Natural Resources Systems Analysis
  • Forest Products Economics
  • Wood Industry Operations Research
  • Wood Physiology and Taxonomy


  • Ph.D., Texas A&M University (1991)
  • B.S.F, Stephen F. Austin State University (1986)

Academic Interests

Analysis of natural resources systems; wood identification and taxonomy; tree physiology; forest pathology; forest industry economics; wood products operations management; process control, simulation, and optimization; statistical quality control; relationships of wood, moisture, product properties, and environmental emissions; artificial intelligence; lean manufacturing; quality management systems.

Affiliated Programs

Penn State Extension

Penn State Biomass Energy Center

Penn State Institutes of Energy and the Environment

Penn State Renewable and Alternative Energy

Professional Affiliation

Society of Wood Science and Technology

International Association of Wood Anatomists

International Wood Collectors Society

Current Research/Educational Projects

November, 2018 – May, 2022. “Quantifying and prioritizing the determinants of wood quality in chestnut variants. PI. Funded by the American Chestnut Foundation.

Recent Research/Educational Projects

September, 2014: “Radio-Frequency Technology as an Alternative Phytosanitary Treatment to Methyl Bromide Fumigation for Wood in World Trade." Collaborating investigator with Kelly Hoover and John Janowiak. USDA CSREES Methyl Bromide Transitions Competitive Grants Program.

May, 2013: "Investigation and Reorganization of the Penn State Wood Collection into an Active Research and Educational Xylarium." Internally Funded.

May, 2013: “Across the Supply Chain: Developing Education and Outreach in Forest Bioenergy." Collaborating investigator with M. Jacobson and D. Ciolkosz. Funded by the Northeast Sun Grant Initiative, US Department of Energy. 

October, 2012: "Project-Based Overview of Woody Biomass Initiatives in the Generation of Thermal Energy and Electricity in the Eastern Region of the United States." USDA Forest Service, in collaboration with Wilson Engineering Services.

March, 2010. “Simulating a Nationwide White-wood Pallet Pool." Collaborating investigator with Judd Michael. Funded by the Pallet Foundation, Alexandria, VA. 

May, 2009. “Simulation of push/pull manufacturing in dimension mill operation." Principal Investigator. USDA Forest Service, Princeton, WV.

April, 2009: “Understanding PA Biomass and 'Energy Wood' – Wood Flow and Availability for Energy Utilization in Pennsylvania". Co-PI with Judd Michael. Pennsylvania Hardwoods Development Council. 

March, 2009: "Project-Based Overview of Woody Biomass Initiatives in the Generation of Thermal Energy, Electricity, and Transportation Fuels in the Eastern Hardwood Region of the United States." Principal Investigator. USDA Forest Service, Princeton, WV. 

July, 2008: “Forest Bio-Energy Techniques and Technologies: Pennsylvania Extension Programming Development from Austrian site visits." Principal Investigator. Penn State Agricultural Extension Seed Grant.

April, 2008:  “Determining Costs, Product Recovery Factors, and Environmental Impacts for Biomass Harvest Treatments in Northeastern Forests." Collaborating Investigator with McDill, et al.  Funded by the Northeast Sun Grant Initiative, US Department of Energy. 

February, 2008: “Establishment of an Institute for Hardwood Industry Innovation and Sustainability." Collaborating Investigator with Michael, et al. Wood Education Resource Center, USDA Forest Service, Princeton, West Virginia.

March 2008: “Wood, Plastic, and Corrugated Packaging Materials: A Comparative Study of Environmental Attributes."  Co-PI with Judd Michael.  National Wooden Pallet and Container Association, Alexandria, VA.

February, 2008: “Microwave Technology Approval and Phytosanitary Treatment Compliance." Cooperating Investigator with Janowiak, et al.  USDA – CSREES, Washington, DC.

June, 2005: “Economic Impact Assessment of International Regulation on the Wooden Pallet Industry and Allied Industries – Topic 1: Assurance of Bark-free Construction."  Principal Investigator.  National Wooden Pallet and Container Association, Alexandria, VA.

January, 2005: “Assessing, Compiling, and Leveraging Lean Production Achievement in the US Wood Products Industry."  Principal Investigator.  Funded by the USDA Forest Service, Princeton, WV.

April, 2004: “Toward the development of a nationally-recognized wood flooring educational program."  Principal Investigator.  Joan Luerssen Faculty Enhancement Fund, Penn State College of Agriculture.

February, 2004: “Extending Education Capacity Related to Sustainable Forest Management to Bulgaria."  Cooperating Investigator with Finley and Luloff.  COAS Seed Grant Program, Penn State University.

January, 2004: “Integration of ROMI optimization engine with dimension mill process flow
simulation." Principal Investigator. USDA Forest Service, Princeton, WV.

June, 2003: “Financial Analysis – Renting vs. Purchasing Pallets."  Principal Investigator.  The Pallet Foundation/National Wooden Pallet and Container Association, Alexandria, VA. 

May, 2003:  “Dielectric and Microwave Applications for the Phytosanitary Treatment of Wood Packing Materials."  Cooperating Investigator with Janowiak, et al.  Competitive Grants Program, USDA – CSREES, Washington, DC. 

April, 2003:  “WoodPro 2004 – A Special Issues Forum for the Hardwood Industry."  Principal Investigator. Pennsylvania Hardwoods Development Council, Harrisburg, PA.

April, 2003:  “Lean Manufacturing for the Value-Added Hardwood Industry." Co-Principal Investigator with Judd Michael.  Pennsylvania Hardwoods Development Council, Harrisburg, PA.  

Peer-Reviewed Publications

Khorshidi, F.H., Azizi, M., Ray, C., Faezipour, M.M., and Hosseinabadi, H.Z. 2021. An analysis of cleaner production planning by applying analytic hierarchy process: a wood industry case study. International Journal of Sustainable Engineering, DOI: 10.1080/19397038.2021.1924893 

 Gargari, R.M., Azizi, M., Ray, C.D., Tarmian, A. and Azam, S.S. 2021. Multiple-Criteria Location Selection for Wood Kiln Operations Using AHP/TOPSIS. Int. J. Business and Systems Research 15(4):448-467. 

Michael, J., and C. Ray. 2020. New protocol for species mix testing in retail mulch samples. Wood and Fiber Science 52:4(2020) 356-364. 

Navabi, V., Azizi, M., Tarmian, A. and Ray, C.D. 2020. Feasibility study on the production and consumption of wood pellets in Iran to meet return-on-investment and greenhouse gas emissions targets. Renewable Energy 151 (2020) 1-20.

Anil, S.K.*, Ma, J., Kremer, G.E., Ray, C.D., Shahidi, S.M.* 2020. Life cycle assessment comparison of wooden and plastic pallets in the grocery industry. J Ind Ecol. 2020;1–16.

Wiedenbeck, J., Scholl, M., Blankenhorn, P., and Ray, C. 2019. Defects and grading after kiln drying hardwood lumber sawn from small-diameter logs. BioRes. 14(2), 4085-4099.

Ma, J., Kremer, G. E. O. and Ray, C. D. 2018. A comprehensive end-of-life strategy decision making approach to handle uncertainty in the product design stage. Research in Engineering Design. 29(3):469-487.

Azizi, M., Asadizadeh, Y., Ray, C., & Hamzeh, Y. 2018. Cleaner production solution selection for paper making – a case study of Latif paper products Co. Iran. International Journal of Sustainable Engineering, 1-11. DOI: 10.1080/19397038.2018.1434701

Mysyk, M, Y, Matsyshyn, V. Mayevskyy, C. Ray, R. Kurka, and I. Sopushynskyy. 2017. “Identification of the length distribution of lumber defect-free areas.” Wood and Fiber Science 49(4), 2017, pp 396-406.

Wiedenbeck, J., M. Scholl, P. Blankenhorn, and C. Ray. 2017. "Lumber volume and value recovery from small-diameter black cherry, sugar maple, and red oak logs." BioResources. 12(1), 853-870.

Azizi, M., F. Rahimi, C. Ray, M. Faezipour, and M. Ziaie, M. 2016. “A decision model for prioritizing geographic regions for cellulosic renewable energy.” Cogent Bus. and Mgmt. (2016) 4: 1249233. 0 citations.

Azizi, M. and C.D. Ray. 2016. “Proposing a decision model for privatization of newsprint paper industry by applying ANP.” Cogent Bus. and Mgmt (2016) 3:1197088. 0 citations.

Azizi, M. and C.D. Ray. 2015. “Introducing a status of access to raw material sources for manufacturers of cellulosic industries.” For. Pol. and Economics 51(2015):17-18. 0 citations.

Ray, C.D., L. Ma*, T.Wilson, D. Wilson, L. McCreery, and J. Wiedenbeck. 2014. “Biomass boiler conversion potential in the eastern United States." Renewable Energy 62(2014):439-453.

Ray, C.D. 2013. “On calculating the green weight of wood." World of Wood 66(6):16-21.

Ray, C.D. 2013. “Soft hardwood, hard softwood, and vice versa." World of Wood 66(5):5-7. 

Ghorbannezhad, P., M. Azizi, C. Ray, C. Yoo, and O. Ramazani. 2013. "Application of sensitivity analysis for assessment of energy and environmental alternatives in the manufacture by using analytic hierarchy process." Env. Protection. Eng. 39(3):5-20. 

Elser, N., J.H. Michael, M. Gagnon, and C.Ray. 2012. “Knowledge Resources and Firm Performance: A Packaging Industry Perspective." Journal of Applied Packaging Research 6(4):225-238.

Ciolkosz, D. E., Ray, C. D., and L. Ma. 2010. “Modeling of Forest Biomass Energy Potential in Pennsylvania." Presented at the 2010 Annual International Meeting of the ASABE. June, 2010. Paper #1008984. 

Ray, C.D., S. Anil*, L. Ma*, J, Janowiak, and K. Hoover. 2010. “LCA and cost comparison of current and proposed pallet treatment methods." Proceedings of the 2010 Meeting of the International Forestry Quarantine Research Group.

Anil, S.K.*, C.D. Ray, and G.E. Okudan Kremer. 2010.  Comparison of Pallet Life Cycle Using LCA and Multiobjective Dynamic Programming. Proceedings of the Thirty-First Annual Conference, ASEM 2010. American Society for Engineering Management.

Scholl, M.S., J.K. Wiedenbeck, P.R. Blankenhorn, C.D. Ray, L.R. Stover, and B.W. Beakler. 2008. “A comparison of kiln-drying schedules and quality outcomes for 4/4-thickness black cherry lumber sawn from small-diameter logs." Forest Prod. J. 58(12):41-48.

Michael, J.H., and C.D. Ray. 2008. “Management decisions in the forest products industry: Where good companies go astray."  Forest Prod. J. 58(10):6-14.

Ray, C.D., A. Laddad*, and J. Ventura. 2007. “The impact of cutting bill variability and product flow for a hardwood dimension mill as determined through discrete event simulation."  Wood Fiber Sci. 39(4):614-627. 

Ray, C.D., J. Janowiak, J. Michael, and H. Bachev.  2007. “Economic and Environmental Impact Assessment of Proposed Bark-Free Requirements for Wood Pallets in International Trade." J. Forest Prod. Bus. Research 4(6).

Ray, C.D., N. Gattani*, E. del Castillo, and P.B. Blankenhorn.   2007. “Identification of the relationship between equilibrium moisture content, dry bulb temperature, and relative humidity using regression analysis."  Wood Fiber Sci. 39(2):299-306.

Ray, C.D.  2007. “The Virtual Extension Specialist." Journal of Extension 45(2).

Ray, C.D., V. Wadhwa*, and J.H. Michael. 2007. "Impact of Overrun on Optimal Performance of Hardwood Sawmills. Wood Fiber Sci. 39(2):291-298.  

Ray, C.D. and E. Deomano. 2007. “Bark occurrence in U.S. and Canadian wooden pallets and containers." Forest Prod. J. 57(3):84-88.

Michael, J.H., Z.G. Guo, J.K. Wiedenbeck, and C.D. Ray. 2006. “Production supervisor impacts on subordinates' safety outcomes: An investigation of Leader-Member Exchange and Safety Communication." J. Safety Res. 37(2006) 469-477. 

J.K. Wiedenbeck, and C.D. Ray. 2006. “Production supervisor impacts on subordinates' safety outcomes: An investigation of Leader-Member Exchange and Safety Communication." J. Safety Res. 37(2006) 469-477. 

Ray, C.D., J.H. Michael, and B.N. Scholnick.  2006. “Supply-chain system costs of alternative grocery industry pallet systems." Forest Prod. J. 56(10):52-57.

Ray, C.D., X. Zuo, J. Michael, and J. Wiedenbeck. 2006. “The Lean Index: Operational 'Lean' Metrics for the Wood Products Industry."   Wood Fiber Sci. 38(2):238-255.

Scholl, M.S., P.R. Blankenhorn, L.R. Stover, and C.D. Ray.  2005.  “Reduction in Kiln Drying Time for Black Cherry Lumber."  Forest Prod. J. 55(12):77-82. 

Ray, C.D., E. del Castillo, N. Gattani*, and P.R. Blankenhorn.  2005. “Time Series Techniques for Dynamic, Real-Time Control of Wood Drying Processes."  Forest Prod. J. 55(10):64-71.

Gattani*, N., E. del Castillo, C.D. Ray, and P.R. Blankenhorn.  2005. “Time Series Analysis and Control of Dry Kilns."  Wood Fiber Sci. 37(3):472-483.

Beakler, B.W., P.R. Blankenhorn, L.R. Stover, and C.D. Ray. 2005. “Total organic compounds released from dehumidification drying of air-dried hardwood lumber." Forest Prod. J. 55(2):57-61. 

Evans, D., J. Michael, J. Weidenbeck, and C.D. Ray. 2005. “The Effects of Organizational Climates on Safety-Related Events at Four Wood Products Manufacturers." Forest Prod. J. 55(6):23-28.

Zuo, X., C.D. Ray, and J. Michael. “Building a Quantitative Lean Manufacturing Transformation Model for the Forest Products Industry.” Conference Proceedings, The Forest Products Society Manufacturing Competitiveness Conference, New Orleans, LA.

Zhang, J. and C.D. Ray. 1998. "Genetic Algorithms for MD-Optimal Follow-up Designs." Conference Proceedings, The Fifth International Applied Statistics in Industry and Manufacturing Conference. Orlando, FL. 

Ray, C. D. 1998. "Forest Products Industry Applications of Systems Simulation." Proceedings of the 32nd International Particleboard/Composite Materials Symposium. Washington State University, Pullman, WA.

Webber, C. L., C.D. Ray, and R.E. Bledsoe. 1997. "Production Properties of Industrial-Grade Kenaf Particleboard." Proceedings of the Fifth Chemical Conference of North America.

Zhang, J. and C.D. Ray . 1995. "Modified Multivariate Evaluation Techniques for Industry-Wide Product Surveys." Conference Proceedings, The Third International Applied Statistics in Industry Conference. Dallas, TX.

Ray, C.D. 1992. “Knowledge-Based Expert System Role in the Integration of Industry Operations.” Proceedings: Knowledge Based Expert Systems for the Furniture Industry. National Pingtung Polytechnic Institute, Taiwan, R.O.C. In cooperation with IUFRO, Project Group P5.08.

Spangler, A.M., C.D. Ray, and K. Hamaker. 1989. “Knowledge acquisition for expert system development.” Computers and Electronics Ag 4(1)23-32.