Acer griseum. Paperbark maple. Maybe a little iffy in zone 5 but most certainly worth the try. This tree has repeatedly been nominated as the best small deciduous tree.

check this link:

http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=c120

10-15' is a very underestimated size for a paperbark maple.....much more likely to be in the 25-30' range and as wide!! However, there are a large number of cultivars of Japanese maple, Acer palmatum, that would remain within that height restriction and virtually all are zone 5 hardy. I would also consider a tree-form hydrangea or Physocarpus (ninebark) for your needs.

If you don't want to waste a lot of time weeding out poor suggestions, provide more information when you ask a question like this. The person who started [this thread[(https://www.houzz.com/discussions/shrub-suggestion-please-dsvw-vd~5675708?n=15) has the right idea, although a picture of the planting site would be most helpful.

A popular multi-trunk tree form in that small size is lilac. Without much effort, it will naturally gravitate toward the tree form and you can help it along by removing lower branches.. There is the benefit of the spectacular smelling spring flowers. A possible downside is its propensity to sucker from the base, creating a thicket if allowed to remain. Suckers are easily removed manually if done early on. Spraying new basal growth with herbicide when it is small & young is more effective

15 ft. is barely reaching into the realm of tree size ranges, maybe you should really be looking at large-growing kinds of shrubs.

It will be invasive in some areas, but if you live where it isn't and it grows in your hood, burning bush makes another good small "tree."

I planted a star magnolia (“Magnolia stellata”). It’s actually a bush but easy to trim up and if you do regularly will look like a tree with a trunk. It is doing great. I’m in zone 6a (coastal Connecticut) but it may be ok in zone 5. Good luck!

Look into Serviceberry, shrub form. Flowering dogwood? Not sure how big they get.

Flowering dogwoods are generally larger but there are a few dwarf forms, though I don’t know how commercially available they are.

There are also some dwarf crabapples that are in that size range, though most crabs are larger.

crabapple chart with height and width

Yay Serviceberry. Also called June Berry around where I live. you get the benefit of flowers and delicious fruit that you can add to your oatmeal or make jam. Or just eat out of hand. I always have some growing in my zone 5 farm yard. Its native in Iowa. It can be tree like or shrub like. It is pretty in the fall with light orange foliage.

My tallest tree in my yard is estimated at 18-20 feet tall and about 10-15' wide. Its about 25 years old, another one has died, so they have a relative short life span.

Berrys:

We purchased three "sweet thing" magnolias several years ago and they are doing very well in zone 5. They are small evergreen trees with lovely spring flowers. Tight profile. Ours are still under 7 feet and we purchased them as large specimens. Max height is listed as 20 feet high, 10 feet wide.

http://www.sweetthingmagnolia.com/

Can you please share your actual location?

If you are in Wisconsin for example a Paperbark maple will take decades upon decades and potentialy never reach 25 feet wide. However it would likely exceed 15 feet in height within a couple decades

Firebird crabapple would stay within your size limitations.

Sargent crabapple stays small.

I’m looking for a similar tree for Zone 5 (Central Iowa.) Cloud 9 flowering dogwood is at the top of my list right now. 10-15 ft high. I’m just looking for one to tuck into a corner to create more shade for my hostas.

I second Dingo's recommendation for a Sargent crabapple. I have one and love it! It has beautiful pink buds that open into white, fragrant flowers. Stunning! The birds love the berries in the Fall/Winter season. Can't recommend it enough. i've had mine for at least 20 years.