Special appreciation is expressed to Charles Vrotney, Forestry Supervisor, in the School of Natural Resources at OARDC in Wooster for his assistance in all phases of this study; without his help, the research could not have been initiated and completed. Appreciation is also expressed to Bert Bishop and Carolyn Britt, OARDC Computing and Statistical Services, for preparation and analysis of research data, and to the Research-Extension Analytical Laboratory for soil and foliar chemical analyses. I would also like to acknowledge the financial and other support provided by the Ohio Christmas Tree Association, Inc., for all of the Christmas tree research programs at OSU/OARDC.