The Silvicultural Significance of Geographic Variation in the White Engelmann Spruce Complex in British Columbia

Abstract

One hundred and sixty-two spruce provenances, representing allopatric and sympatric populations of white, Engelmann, and Sitka spruce in British Columbia were sown in a coastal nursery. Twelve of these provenances were randomized in four replications, two of which were of regular nursery soil and two of an artificial soil mix. One hundred and fifty were randomized in six replications, all of which were of the artificial soil mix. In the second nursery year a plastic greenhouse was placed over two replications of the 12 provenances.An assessment of the growth behavior of all provenances showed a strong correlation between time of entering dormancy and geographic origin. A high correlation between time of entering dormancy and total growth is also demonstrated. The dormancy curve is shown to characterize a provenance with some accuracy.High-elevation provenances, which were the first to enter dormancy, were stunted in growth and exhibited a "rosette" appearance as a result of decreased internode length, while certain low-elevation provenances from the interior of British Columbia grew as well as Sitka spruce.On the basis of these results, recommendations are made in regard to the propagation of interior spruce in coastal nurseries, both in the open and in plastic greenhouses, and in regard to the displacement of spruce provenances in the interior of British Columbia. It is emphasized that these recommendations are tentative and will be modified as information accumulates concerning the genecology of white and Engelmann spruce in British Columbia. A major source of new information in this respect will be the long-term field trials that followed the study reported here.