The Real Christmas Tree Board

The increasing interest in growing exotic firs, such as Nordmann, Turkish, and Trojan firs, as Christmas trees in the United States is limited by the inconsistent availability of seed from proven high-quality seed sources of these species. Although there are currently a number of small domestic Nordmann and Turkish fir seed orchards and recently established Turkish and Trojan fir seed orchards resulting from the recent CoFirGE trials, for the foreseeable future the use of these species will depend on seed that is imported from native tree stands in the Republic of Georgia and Turkey.

Many conifer species’ seeds can be stored for decades without considerable loss of viability and vigor. However, several true firs (Abies), have notoriously poor seed storability. Nurseries in the Pacific Northwest indicate that the viability and vigor of Nordmann and Turkish fir seeds degrades significantly after just one or two years in cold storage. There are numerous facets to current harvesting, processing, and storage practices that may be contributing to subpar viability and vigor. The moisture content that seeds are dried to and the temperature they are stored at are two important factors that affect the viability and vigor of stored seeds. Seed importers have commonly noted that the MC of imported seed tends to be in the 10-12% range. In the Pacific Northwest, conifer seeds are commonly stored at moisture contents of 8-10% and temperatures of -10 °C (15 °F). Several studies of Abies species, including one of Nordmann fir, indicate that a lower seed moisture content of 6-8% and a storage temperature of -18 °C (0 °F) can better maintain seed germination (viability) and vigor when stored long-term.

To examine the influence of MC on initial seed quality, tests were conducted to assess germination, enzymatic activity, accelerated aging, and speed of germination of domestic and imported seed that were dried to a range of moisture levels