I'm not sure what it is you are describing :-) Multi-stem meaning multi-trunked? Or a collection of 4 main branches emerging from the trunk? Maples - and most other shade trees for that matter - do not maintain a single predominate leader as they mature (the term is "decurrent") but rather develop a collection of codominant branching. If the "multi-stems" you are describing are branches that emerge from the central trunk at an appropriate height, are well spaced and without tight, narrow crotch angles, you should be fine.

Posting a picture would clarify things, tho :-)

This autumn blaze maple is a multi-trunk tree. There are 4 main stems coming out of the ground.

That sounds like a mistake.
'Autumn Blaze' Freeman's maples should be grown with a central leader.
Was the place you got it into doing weird things with trees like shaping them or training them to grow in artistic ways?

No they really just have the basic stuff. They grew that way as there are many multi trunk maples in their field.

Its definitely a freeman maple. I just always knew them as single trunk trees. The multi trunk struck me as more interesting but didn't know about their reliability.

I can't think of too many planting situations where a 40' tall multi stem silver maple hybrid is convenient or a good idea, that's all. I've never seen clump maples sold before so that's a new one for me. It's not like a river birch or Aspen which is multi stem for the attractive bark. On the contrary, freeman maple bark gets damaged easily because its so thin and even down south they get crack in the winter. But even Biches and aspens are a better idea in groups than in clumps if you ask me.

By the way if you have a photo of a clump maple used nicely in the landscape, I'd love to see it.

I talked to the nursery and basically there comments where...

Its tough to find a clump maple with multiple trunks so the actual look of the tree is much more interesting.

Based on horticultural practices a multiple trunk tree is not desirable because of the potential issues of a mature tree. The said the trunks "could" split in 20 - 30 years...but that is not guarantee.

My consensus its that its a small investment, its an open area and won't be considered a "high" value tree. Its in the corner of my back lot so its just for looks.

I get it delivered in one week so I'll post a picutre. Its already 14' tall.

IF you haven't taken delivery of it, I think you should reconsider and plant a desirable tree for the long term.
There are plenty of attractive trees that are in investment for future generations to enjoy. Buying a clump maple that is going to fall apart in a wind storm and be an expensive removal job is no different than planting a cheap bradford pear. There are so many truly interesting trees that are better than a silver maple hybrid with multiple stems.

That evaluation is pretty subjective :-) Clump form or multi-trunked maples don't necessarily have structural concerns - no more so than many other trees. As the nurseryperson said, "no guarantee" it could split in 20-30 years. And they do have value - multi-trunked specimens of Japanese or paperbark maples tend to demand a far greater price tag than their single trunked cousins. The immediate sculptural effect of the multiple trunks is highly desired by many landscapers and homeowners.

My native bigleaf maple, Acer macrophyllum, is very common as multi-trunked tree and there are scores of them growing naturally as well as under cultivation that have been around for decades. And we can have some serious windstorms here - strong enough to blow over Douglas firs and western cedars by the dozens.

Here's a photo of a multi-trunked paperbark grown locally:

and one of a big leaf in fall color:

We just need to get out of the mindset that all shade trees are somehow "better" or more desirable if they are grown as a single trunked, single leadered specimen. It's all a matter of choice.

I love those clump paperbark maples. I've only seen a couple before and they are pretty dang expensive since they are such slow growers. Chicago's botanical gardens had a nice mature one.

Silver Maples in my area don't have too many issues with wind storms...its rare if we get 40 MPH gusts in any given storm.

I really chose a Freeman maple, because its going in a hot, dry and clay soil area. Not too many choices for that condition. I have a regular Silver Maple on the other back corner of my lot and its quite gorgeous. If pruned properly they are fantastic trees given they have an open area...especially for hot, dry and clay soils.

Pictures to be posted next week.

IMHO is that Freeman maples serve a purpose. They are not nearly as fragile as many would have you believe. This was demonstrated by a recent exceptional ice storm. Those that I know of locally, survived with little to moderate damage. ALL species incurred damage. Oak, maple, hickory, whatever, didn't matter, all of them. And the freeman maples were no worse than any of the others.

There seems to be a strong bias on many garden forums, that if its not slow growing, and live for 500+ years, then it's not worth having. Never mind that the planter will never see the results of what they sow, and for that matter the next owner may just hate it, and cut it down. This attitude is horse fertilizer. And in the case of your Autumn Blaze, I would bet it will cause no trouble barring extreme circumstances, for many decades, as is the case with silver maples. At such time as they do fail, so what, as long as they aren't overhanging 3 houses (this happened to a friend in the recent ice storm; biggest silver maple I had ever seen by far, with probable a 5'-6' dia. trunk). All trees will die, just because they are long lived, does not change the fact they will be removed by some method eventually and will fall to the ground.

As long as it's not invasive in your area (that's another debate), plant what you want, and enjoy as long as you are aware of the potential results.

JMHO
Arktrees

We have a multi trunked maple that we planted in 1978 in eastern Washington in very gravelly soil. It is about 60 feet high and very symmetrical in appearance. Only trim a few lower branches as half is over driveway. It is beautiful and adds greatly to our landscape.
No mistake or hibrid here. Collected from the country side where there were lots.

I would leave it as a multi trunked tree. Especially since you say that the 4 stems are evenly spaced and of equal size. I think it will look great. I have been trimming some hickories by me as clumps for the last 12 years and they are looking good.