You tell him "NO" ! Don't do it! Plant the hostas someplace else and do not suffocate the tree.

Beech trees naturally have large, exposed roots - do NOT cover them! You'll suffocate the tree.

Listen to quirky. Those roots are on the soil surface for a reason. Adding soil will not kill the tree overnight, but irrevocable damage can be done to the tree that could cause the tree to die over several years. Beech trees have very dense shade and that is why no grass grows under the trees.
Mike

Have him remove ALL the soil AT ONCE. He should NEVER have put it there, but as long as the tree was dormant, the tree probably took little harm from it. Leaving it, on the other hand, is a BAD, BAD, IDEA!!!! He can use the soil to make a bed somewhere elee in the yard, preferably NOT right under another tree.

That's how beeches and their roots grow, and that's how they WANT to grow. Mulching lightly - up to 4" - with a hardwood mulch, over the whole area can give it a more "pulled-together" look, if you want. Or you can just leave it, as you have been doing.

Planting almost anything under trees and over tree roots, especially trees with roots near the surface, is a losing proposition. The tree roots and the plant roots compete for the water and nutrients, and the tree, being so much bigger, usually wins.

Unless you have a contract with this landscaper, IMO, you might want to think about finding another one, with a bit more knowledge. It may look "pretty" to some people, but circles of plants under established trees is a bad idea as is leaving dirt piled thickly over tree roots.

And his is why I don't trust anyone except horticulturalists and arborists. Sorry to be so blunt but this guy is an idiot and you are a genious for questioning him. Besides all that...I agree its looks silly when people plant in rings around beautiful established trees. Who cares if there is not grass growing there...its a a lovely tree. I think this guy is lazy and doesn't want to haul dirt. Absolutely tell him to get lost with his uneducated ideas. Good luck!!

Thanks to all of you for your quick response. I should say that really our landscaper is terrific with grass, shrubs, etc, (he's done work for us for 15 years) but obviously doesn't know anything about trees. Fortunately it's been cold in CT until we got a few warm days last week. I called him and asked him to remove the dirt ASAP and the best he could promise was by Friday, although he'll try to do it earlier. Right now the roots farther away from the tree are exposed. On one side the roots are entirely exposed, on two sides they are about 50% exposed, but on one side I would say only about 20% of the roots are exposed. Do I need to get out there with a shovel now, and expose some more of the roots?

If the weather will be quite warm, and the tree is actively growing leaves, then it might not hurt for you to expose more roots. If it will stay relatively cool, and the tree is only now leafing out, it can probably wait for him to do it. If you do have a sturdy teenager on hand, this might be just the thing for him/her to build up some arm and back muscles!

If you trust your landscaper for other things, then fine, but for your trees, get a certified arborist, or do some basic reading yourself - and trust to your instincts and common sense. It would seem that they are right on track!!

My beech tree fell down when the storm came last week and it had red blood to its bark I’m wondering was it damaged by some one who decided to do damage to weaken it and it fell then it’s roots are shown and there is a fine bark in the garden to see how stable it was .It was like 12 years old and in perfect condition we are devastated!!