The relatively short, cool growing season for most spruce sites and its sensitivity to frost requires careful attention to timing of planting, spot preparation, and selection of planting microsites. Check the species prescription for spruce is suitable for the site conditions after logging. Consider the risk of frost, winter desiccation, terminal weevil, and seasonal drought before finalizing the species selection. If in doubt about the acceptability of Sx, consider substituting or augmenting the planting with Pli or Bl, consider the potential for site preparation, and make the best use of microsites to protect the seedlings.
Plate 20. Sx stock types. (Arrowheads indicate target heights.)
The major limiting factors that Sx stock type selection can address are vegetation competition (herbs, shrubs, and grasses), snowpress, and duff depth. Vigorous seedling performance is crucial to overcoming these limiting factors. To address vegetation competition and/or snowpress, select stock types with a high sturdiness ratio and do not accept reductions in the root collar diameter specifications.
For the most severe vegetative competition, the PSB 415D 1+0 Sp and/or 2+0 Su or larger stock types are recommended. The compact top and good sturdiness ratio of the PSB 410, PSB 412, and PSB 512 1+0 stock types may be advantageous for sites prone to snowpress.
Sx is often planted on sites with a high frost heaving hazard (exposed moist fine-textured soils) (see "Frost and winter desiccation"). Growing Sx in PCT containers to promote upper plug rooting may be advantageous in areas of high frost heaving and/or winter desiccation hazard.
|Sx stock type suitability.|
|Animal damage||Shallow soils||Fine-
|Recommended stock types:|
|PSB 313B 1+0||Sp, Su||Poor||Poor||Poor||Fair||Fair||Fair|
|PSB 410 1+0||Sp, Su||Poor||Fair||Poor||Good||Poor||Good|
|PSB 415B 1+0||Sp, Su||Fair||Fair||Fair||Poor||Good||Poor|
|PSB 412A 1+0||Sp, Su||Fair||Good||Fair||Good||Fair||Good|
|PSB 415D 1+0||Sp, Su||Good||Fair||Good||Poor||Good||Poor|
|PSB 512A 1+0||Sp, Su||Good||Good||Good||Good||Fair||Poor|
|PSB 515A 1+0||Sp, Su||Good||Good||Good||Poor||Good||Poor|
|PSB 615A 1+0||Sp, Su||Good||Good||Good||Poor||Good||Poor|
|PSB 415B 2+0||Su||Fair||Fair||Fair||Poor||Good||Poor|
|PSB 415D 2+0||Su, Sp||Good||Good||Good||Poor||Good||Poor|
|PSB 515A 2+0||Su, Sp||Good||Good||Good||Poor||Good||Poor|
|PSB 615A 2+0||Su, Sp||Good||Good||Good||Poor||Good||Poor|
|PBR .5+1.5**||Su, Sp||Good||Good||Good||Poor||Good||Poor|
|PPT 515A .5+.5||Su, Sp||Good||Good||Good||Poor||Good||Poor|
|*||Particularly significant in boreal forest areas with low snow cover (e.g., Peace River).|
|**||Suitable stock type if a) handling requirements can be met, and b) soil depth is greater than 30 cm.|