Special appreciation is expressed to Charles Vrotney, forestry supervisor in the School of Natural Resources at Wooster, for his contributions to all phases of this study.
Appreciation is also expressed to other OSU/OARDC School of Natural Resources personnel - Dr. Dan Houston, associate professor emeritus, for assistance in cone collections; Clay Dygert, research associate, for assistance in collecting cones and establishing and maintaining the experimental area; and Marie Semko-Duncan, research associate, for assistance in making field measurements.
Appreciation is also expressed to Bert Bishop and Carolyn Britt, OARDC Computing and Statistical Services, for preparation and analysis of research data.
I would also like to acknowledge the Pennsylvania Christmas Tree Growers' Association for their financial support of this project and the Ohio Christmas Tree Association, Inc., for their financial and other support provided for this and other Christmas-tree research programs at OSU/OARDC.