Is This A Young Walnut Tree? Or A Weed Tree?

No...not that kind of weed tree.  I'm talking about a weed tree that has grown up and isn't really much of a desirable tree.  Or, is it a Walnut tree?  You can see the trunk being very tall and thin.  The tree is twelve or so feet tall and has a set of leaves that look just like Walnut tree leaves.  We have quite a few large Walnut trees around the yard, so it isn't beyond reason that a Walnut would have rooted and grown into a tree, I would think?

The leaves of Walnut trees are "alternate compound" or "pinnate leaves" and so, too. are the leaves of this tree.

I know a little bit of the Black Locust tree - which is (I think) a "weed tree".  It has similar shaped leaves, but the tips are rounded where these are pointy.  It is "not recommended" by the Morton Arboretum.   I'm pretty confident that the tree in question - in the red circle - is NOT a black locust.  

But, is it a Black Walnut tree?  

Here's a closer look (below) at the leaves with their pointy tips - and you can tell they're NOT Black Locust.

Last year, I limb'd it up and left it in place, so it is now long and lean.  That shape - and the high growth rate in height has me concerned that it isn't a desirable tree.  I mean...I've put in a bunch of trees and NONE of them are this tall with this thin of caliper.  But, it is in the back part of our lot with quite a bit of shade, so perhaps it is growing up to get some light?  

I found this image of what is labeled a '2 year old Walnut tree' that has some of the same characteristics as my tree.  Another data point in favor of this being a Walnut tree. 

It also has NOT bore any fruit yet - which...would clear up any confusion. However, the folks at the Balkan Ecology Project say that young Walnut trees don't throw off any...well...walnuts:

Walnut trees commonly reproduce in the wild and are very easy to grow from seed. A tree grown from seed will start to produce fruit in 8 -12 yrs.  

Eight to twelve years before fruit. 

But, there are other trees that it might be?  Tree of Heaven?  Sure looks like it might be?  Check out the images in this Penn State University Extension video.   But, in the same video, the expert lists some Tree of Heaven "look-alikes" and includes Black Walnut.

So...there seems to be sufficient evidence that this *might* be a Walnut tree, right?  But it also might be a Tree of Heaven or even a Sumac - despite it not flowering.  So, it is unclear.  But...there seems to be at least enough uncertainty to say that I should keep it in place another year and NOT take it down.

Maybe this is something else that I should add to my 2020 list of to-dos:  snap some pics and ask the Master Gardener what the tree is when it leaf's out next Summer.    They helped me identify a couple of small American Elms last Summer, so I'm hopeful they'll figure these out.