Sure looks like a tree not sure what type. When I see volunteer trees on metro area properties I usually recommend they remove them before they get too big. Yours is in your natural area so it's probably ok unless it's something that is an invasive species.

Sure looks like a tree . Can you post close up pics of several leaves?

Possibly an Elaeagnus species.

I agree with bboy, Elaeagnus angustifolia or Russian Olive with those pointy leaves. It's on the noxious list here in Colo. which would sway me to remove it. Some folks on our plains like them for wind breaks, but in the urban environment I think they should be removed. They will sucker from the cut stump if left untreated, so that tells you how hard it may be to rid your natural area of it if you decide to leave it and subsequently change your mind. Hope this helps.

I agee - it looks like Russian Olive! If it has thorns (may not have developed yet), than it's sure to be RO. That's the main thing I don't like about them - nasty, nasty thorns!!! We have two in our yard that were here when we bought the place. The tops have made a nice screen from the neighbors, but one of the trees started dieing at the top, so we had to chop it down. We left the trunk base, as it had been suckering so knew it was still alive. I've been trimming the suckers back, and letting one stronger one continue to grow behind the main trunk. I may decide at some point to get rid of the whole tree, but for now I'll let it go.

I know these are considered weed trees, but other than the thorns (especially noticeable when getting rid of the branches from the dead top!!!), I've been fine with it. You do have to stay on top of the suckers, though - very prolific that way. It appears to grow very quickly, so in that respect, it makes a good choice when you want to tree for screening in a short period of time.

Marj