Answer: Depending upon the size of your spruce, you'll find most of the roots in the top 12-18" of soil, extending out at least as far as the branch tips. Most of the roots that venture out that far are feeder roots and can be severed if you plan to move the tree. Severing the roots about halfway between the trunk and the outermost branch tips will result in a more compact root mass if you're digging the tree. If you're concerned about roots invading the foundation of your house, or lifting a sidewalk or driveway you can place a barrier between the tree and the hardscape or foundation. Typically the roots are not invasive, but it depends upon how close the tree is planted to them.
Hope this answers your question.
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