Long-term seed storage of various Canadian hardwoods and conifers

The National Tree Seed Centre has been collecting, storing and testing seed for over 35 years. During this time, a large database has been amassed which we use here to assess the potential of 15 species for long-term seed storage at -20degreesC. Seed moisture content and storage temperature are the two most important variables that impact seed longevity. The data show that seed stores well when moisture content is below 9%. For Picea glauca and Acer rubrum, for example, seed moisture contents exceeding 9% had a strong negative impact on storability. Survival curves for Betula alleghaniensis, Picea mariana, Pinus banksiana, Pinus resinosa and Populus grandidentata showed seed viability declined very little after 14 to 32 years in storage. As well, germination data from selected seed lots, 30 years old and older, of Picea glauca, P. mariana, P. rubens, P. sitchensis, Pinus banksiana, P. contorta vat. latifolia and P. resinosa indicate the functional storability (germination > 60%) of these species may be as great as 100 years when stored at -20degreesC with seed moisture contents less than 10%. Factors affecting storability, such as initial seed quality, seed moisture content and storage temperature are discussed.