Douglas fir, Pseudotsuga Menziesii (Mirb.) Franco, is a popular Christmas tree in the Northeast. In 1976 trees from 11 geographic sources ranging from British Columbia to southern Arizona and New Mexico were planted in a replicated design and managed as a commercial plantation. Information was also obtained on 10 seed sources grown on a commercial tree farm. All sources were hardy in the Connecticut plantings. In general, trees from southern Rocky Mountain sources were bluer, and grew faster than those from northern sources, but they were also more susceptible to attack by Cooley gall aphid, Adelges cooleyi (Gill), and rhabdocline needle cast fungus, Rhabdocline pseudotsugae (Syd.)
Author notes
We gratefully acknowledge the following for their assistance in supplying seedlings, growing trees, cultural care, or recording and evaluating data: Peter Cumpstone, Nancy DePalma, Claude Heit, Phillip Jones, Gerald Walton.
2Present address: Broken Arrow Nursery, 13 Broken Arrow Rd., Hamden, CT 06518.
3Horticulturist, Forester, and Plant Physiologist, resp.
