Bed expansion for future plantings and to improve root zone for existing native trees. Midway or so string trimming the grass to nothingness. Killing grass is wonderfully fun. Follow that with chopping up the grass debris and a bunch of fallen leaves with a mower. No sense in pulling up the sod as the trees have a ton of shallow roots there. Plus the decomposing grass roots and thatch will provide some free OM and improve structure a bit as it breaks down. No need for stirring with an air gun, soil isn't compacted and shows pretty good aggregates. Mulch and some plants to follow, hoping for a small snakebark maple to drop in. I grow bottle brush buckeyes from seed so those can go in plus some perennials.