We live in an area where we burn leaves and other yard waste.
Would the resulting ash be high in trace elements and be good
to sprinkle around plants?

Why do that, they make wonderful compost or mulch for the plants if you chop
them up with the mower. I put a huge pile out in and area I'll be planting in
next spring, hoping to amend the area as much as I can naturally.
Colleen Ann
Zone 5 CT