Is the soil contaminated? If so to what degree? Can one replant a spruce? Is there another conifer that would be less risk? Austrian pine? Balsam fir? Arbor vitae? Concolor fir? I am thinking it would be wise to take a few soil samples, maybe 2 inches, 6 inches and 12 inches deep. Plant something sensitive in the soil in flower pots. Say cucumber, beans or tomatoes. Observe the results after 10 days. Compare with clean soil. Does anyboy have access to spruce seeds or tiny spruce trees? White pine? Perhaps mix soil samples with water, filter out the soil and spray the (possibly contaminated with Imprelis) water on tomato plants. Or spruce trees.