Depending on how thick of a layer of that chicken manure-compost combo you plan on applying, I'd say this was not a great idea. Sorry.

Raising the soil level around an established tree has the potential to smother the root system, depriving it of oxygen and eventually killing the tree. And if you planned on planting shrubs, you would need a pretty thick layer of the stuff to accommodate the rootballs without disturbing the birch roots. And being just organic matter, it will soon shrink and expose the shrub roots. Even without layering on any amendments, you would have a heck of a time trying to plant shrubs in that area without terrorizing the birch roots.

You might be able to get by with plugs of drought tolerant, spreading groundcovers.

Anything would be better than what was there previously.. ’m definitely open to groundcover, if shrubs are too big then so be it! Any suggestions for ground covers? We are in Zone 9 and this area is full sun.

Oh and we won’t be doing a thick layer. Sprinkle manure and compost, hand mix around the loose soil to break up the clay in the top 2-3 inches. Will definitely be mindful of not making it thick and I do know we need to keep the soil level around the tree trunks the exact same!

Zone 9 where? It makes a difference. And the concern is not so much about raising the soil level around the trunk (although that too is never a good idea) but more the impact of the increase to the entire under-canopy area. 2-3 inches of soil is too much.......2-3 inches of compost not so bad as it will continue to reduce with time.

What I mean is that as I break up the old compacted soil, I’m only aiming to break up the top two or 3 inches, I was planning to mix in some compost which includes composted chicken manure. Not raw. So the total top layer would be 2-3 inches but only like 1/2” of that would be “new” stuff aka the composted manure. Zone 9 Bay Area, it’s hot and dry but where we are does get more fog and rain in the winter than other parts.

I live in zone 6..I have half an acre with lots of trees..I've avoided planting near my trees..in this pic there's lamium galeobdolon spreading everywhere..I pulled quite a bit out last summer..this is a spring pic before the trees are fully leafed out..seems sunny but that's short lived..

you have full sun..would scattering seeds of some kind work?..

Don't try and amend the soil. You can't add enough to make much of a difference and trying to work it into the soil amongst all those roots without damaging them would be a Herculean task!!

Go to a local nursery/garden center and see what groundcovers they offer that fit your situation. A coupe of natives that come to mind are dwarf manzanitas, Ceanothus gloriosus or griseus or prostrate coyote bush. I also like creeping raspberry, Rubus calycinoides. And a variety of cranesbill or hardy geraniums or creeping thymes could work as well.

Purchase in as small a size as you can find and then much lightly in between with your amendment mix.

Makes sense. Thanks!! I’ll look up the ones you suggest!

Ended up cleaning up the soil and planting in the shallow topsoil. No roots her disturbed in the making and I have zero regrets!!

Have you had any problems with your birch roots growing into your lawn?

That looks beautiful J L.

Cyndymn not that I can tell.

Thank you toxcrusadr!