Published online by Cambridge University Press: 05 December 2011
Because of the wide latitudinal range of Sitka spruce, trees of different origin show very large differences in growth rate and adaptability when grown on a variety of sites in Britain. The Forestry Commission has forty-eight seed origin trials, planted between 1929 and 1975, which are now beginning to provide a good overall picture of this variation. On the other hand, differences in morphology and colour are relatively minor, so that it is very difficult to identify the seed origin of a stand of trees on visual grounds alone. Southerly origins (below Latitude 47°N) grow fastest, but they suffer more severe frost damage, particularly in the nursery, and tend to have lower density timber than those from 53°N or above.