Tree ID

This is growing aggressively from runners along the tree line.

Maybe some kind of ash?

That could also be a Walnut tree. the Ash family has opposing paired branches, the Walnut family has alternating branches. It definitely isn't a Hickory.

i agree with bryant, it looks like one of the walnut family of trees- Juglans.

not sure which one, or if it is for certain, but thats the same kind of leaves walnut trees have.

Ah, I had those growing at my last place. Can't remember what they were. Lots of offset seeds with a wing: they "helicopter" when they fall.
Have to ask if anyone remembers what it was...

Growing from runners says sumac to me. Also your second picture has what looks like the flower bunches that will turn into the tell-tale berries.

o yeah,
i bet thats right. sumac.

its not quite exactly like walnut, but close.

Thanks for all the responses. The trees are in Eastern West Virginia if that helps. The leaves seem to grow only on the very ends of branches. The bark looks grey to me. They are growing in a hedge row along with Oak and Cherry. Should I keep them away from the other trees?

I agree with Jessica . Sumac .

Definitely Rhus thypina or Sumac
Wikipedia-Sumac

This looks like Ailanthus to me. Sumacs don't have winged seeds that blow around, they have berries, some smooth and some furry. Ailanthus can also get taller than any sumac, almost as tall as the general canopy of trees in the background. The leaves also have a peculiar unique funky smell, again unlike any sumac, whose leaves have not much smell, or walnut, with a not unpleasant kind of solvent smell.....
Ailanthus is considered an "invasive exotic" in many places where it grows, but it has the ability to survive where many plants cannot, and might be a valuable pioneer on degraded sites. Supposedly it can grow in straight coal ash or mine spoil, and the book "A Tree Grows in Brooklyn" is named after it, where it comes up in cracks through the pavement..... I'm not aware of any practical uses. Most animals won't touch it, and the wood is light and not much worth burning....

My vote is for Sumac. If it gets red berries on the top later in your year, that is your plant. I have oodles on my property. Later this year, you will find out (if you get those red berries)

alder burns is correct
Ailanthus altissima Tree of Heaven

Ah!
Eww!
Tree of heaven. I agree with burns. Ailanthus altissima. Tree of #$%& is more like it....

In the second photo above are those berry clusters forming ? Look dead center of the photo . Red and conical like a sumac perhaps ? Or new leaf buds ?

https://www.youtube.com/watch?v=3hxhStqc-3M&index=150&list=WL
video on how to use sumac spice