Pal, it seems the nearby power lines will be the limiting factor here. Therefor, all full-size shade tree species would not be the best choices. Why plant something that is eventually going to get hacked on by line-clearance people?

There are still numerous choices. What are some other factors you'd be interested in? The redbud for example, is obviously a favorite. I'm no expert on St. Louis tree growing, but that could work.

+oM

Where are the power lines in relationship to your planting site?

Depending on that perhaps you can go after a species that grows fast while young but then slows with age...ie Oystra virginiana

There's someone on this board who likes to recommend chalk maple, which is basically a smaller version of sugar maple. Maybe he'll chime in.
For smaller shade trees I like sourwood (Oxydendrum arboreum), American hornbeam (Carpinus caroliniana), yellowwood(Cladrastis kentukea), dogwood (Cornus florida), and blackgum (Nyssa sylvatica). I love anything if it's native.

Ug. You are having to replace one of the best.

Sweetgum is one of the few fall color rivals. Enjoy the spikey balls. Perhaps there is a thin cultivar out there.

I'm big on native, too.

Power lines are currently running through the limbs of the maple to the house. Hence the city's recommendation of the more upright European Hornbeam.

I really want a tree with a beautiful canopy, but I know the power lines will prevent that, so a smaller tree will have to do. Acer and Whaas, I'll talk to the city arborist and the local nursery about your suggestions.

Without a shade tree there, we will probably never use the boiling hot brick patio from July - mid September!

And since I have TWO sweet gums in front ... I'd rather avoid spikey balls in the back yard, too, thanks all the same! :) But you're right, they are beautiful trees!

I just wish my back yard were large enough to plant another sugar maple somewhere else. It's my parents' house, and I have many fond memories of sitting under the tree with them and watching the foliage change. Cutting it down is going to devastate my 93-year old dad since he planted it with mom, but it's beyond saving. According to the arborist, they planted it too shallow, and the past few years of severe weather have stressed it. Now it's rotting from the inside out, and splitting as well.

Thanks for all of your suggestions!

My thought is tulip tree. Wood is reasonably strong, and its a fast grower. Also it often stays rather narrow even in the open, at least for a while.

If you want a tree there, and don't MIND that the limbs near the power lines may get hacked off by the power company one day, I say go for what you want. Just keep it in mind.

Palomita, you said " planted too shallow". Sure you didn't mean the reverse, planted too deeply? Very seldom was any tree ever planted too shallowly, while the act of planting trees too deeply continues much too much to this day. Just wondering. that really jumps out at me as an odd statement.

Sugar maples are among a group of species which are particularly sensitive to a too-deep planting.

+oM

Nope. The arborist said too shallow. And now it's down. I am definitely going to look into the Chalk Maple, as well as the other suggestions and see how much of a tree I can afford to plant. I'm hoping that this Isaac rain is the beginning of the end of the drought here, and we'll be able to plant in October.

serviceberry or amur maple might take the heat. They don't grow that fast though. SW sucks. Maybe try a smaller magnolia like 'Leonard Messel' or 'Merrill'. They have awesome early spring flowers and will take the heat, but again don't grow super fast.
Crabapple might work but I have not tried growing it...

Serviceberries are lovely! ... but as it is right next to the patio, I'm not sure I want to deal with the fruit so close to the house. (I have rather fond memories of a mulberry in back, but my mother was not so enamored of our purple feet!) And since it goes through power lines, I don't want an attractive nuisance for children. I also love magnolias, but they are finicky here in St. Louis due to the unpredictable weather. I have seen some HUGE specimens here, but they aren't common. Beautiful though.