Hi,

I would advise against any trenching. You have a huge, well established tree and you don't want to be cutting any of the tops of the roots.

https://uwlab.soils.wisc.edu/soil-samples/lawn-garden/

The trees (all of them) should not have any grass growing around them. The grass competes for water and brings the mower closer to the trunk. Get rid of the grass ! I know this sounds like a big task, but, do you want healthy, beautiful oak trees ? Isn't that the goal ? Gently pull away all that grass and lightly much around the trees. The main root flares should be should be exposed to light, not covered with soil. They need oxogen.  Make a border with shade loving perennials instead of bricks. Wild Ginger would probably work well.

The last question about the bending tree .... it depends, oaks look so fantastic when they are aloud to bend down. It sounds like you want it to go straight up. It's your preference. Some of the most spectacular trees I've seen have long leaders that bend in great arches and touch the ground.

I hope this helps,

Sally Granath

St. Louis County MG