Can you successfully plant a new tree on top of an old stump?
I planted a street tree 15 years ago where no tree had existed for the past 100 years. It was a Raywood ash, approved and permitted by the Multnomah County arborist. It grew to a handsome 60 ft. tall, then was fatally damaged during a windstorm this past winter. I had the tree removed, with the approval of the city arborist, and the 24" diameter stump was ground to 8" below ground level. The city requires that I replant over the stump. There is no other appropriate site in my planting strip. Other spots would either be too close to my driveway or too close to another tree. Will another tree thrive there? On top of a 2 ft. diameter, platform of a stump? I'd like to petition the city to NOT replant a tree but instead some shrubs. My argument being that planting a new tree there would simply doom it to failure, given the lack of space for any healthy root growth. Your feedback would be much appreciated!
I would be concerned about a new tree's ability to thrive being planted right on top of the previous one. It would depend, in part, on the extent of the stump grinding job. The majority of a tree's roots are within the top 3 feet of soil, and 8 inches is a somewhat minimal depth to plant right on top of. Part of it may depend on how far out from the base of the original tree that the roots were ground up.
So, I think you've got a good argument, but I'd guess that an onsite conversation with one of the city's tree inspectors, armed with a good soil probe, might render a reasonable solution.