Field performance of micropropagated Douglas fir

In March 1981, Weyerhaeuser Company established a field trial across five sites in coastal Oregon to test performance of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco plantlings derived from cotyledon explants through tissue culture. Main objectives of the trial were to (1) compare survival and growth of plants produced by different propagation techniques (stock types) from the same genetic material, (2) compare field performance of plantlings derived from select orchard families with that of plantlings derived from local wild seed, and (3) assess the effects of size and form at planting time on subsequent plantling performance. After 5 years, survival in the stock-type trials was 91 % for plantlings, 99% for seedlings, and 49 % for rooted cuttings. In the larger family comparisons, plantlings exhibited 74 % survival. Owing to smaller initial size and 1 early year of reduced growth, plantlings are now 11 % shorter than seedlings but both have had the same height increment during the past 3 years. Rooted cutting