Douglas Fir Trees Losing Foliage How To Repair The Soil

Question From: Portland, Oregon, United States
Q: I have four 75' + Douglas Fir that are currently losing foliage. I cannot afford the $6K an arborist bid to fertilize and reduce the soil compaction. How do I repair the soil compaction and amend the soil and fertilize them to reverse the foliage loss?

A: Doug Firs are shallow rooted so the arborist would use an air spade to loosen the soil. You can't dig or rototill because you will damage the roots and probably kill the trees. That price seems high, I'd get some other bids.