The effect of stratification and artificial light on the germination of mountain hemlock seeds

Germination in mountain hemlock, Tsuga mertensiana (Bong.) Carr., was investigated using 19 seed sources from British Columbia. Neither light nor stratification for 28 days had any significant effect on germination capacity, but light significantly (p ≤ 0.01) reduced germination rate. Stratification significantly increased germination rate in all seed sources, although the amount of total variation attributable to this effect was small. Stratification did not overcome the effect of light, and it is recommended that seeds should be covered after sowing in the nursery. All sources, including one from the interior of the province, germinated relatively uniformly. No correlations could be found between germination parameters and age, source elevation and seed weight, but germination capacity and seed weight were correlated with latitude. No correlation existed between seed weight and elevation. For most sources, a test duration of 21 days was adequate for complete germination even of unstratified seeds. Mountain hemlock seeds should be stratified before being sown in the nursery, and they should be covered during the germination phase to exclude light.