...the leaves are wrong for Eucalyptus, which are stiff and leathery, with oil glands. the pic looks much too 'soft' Yeah, not sure of 'softness' or vein color from photo, know next to nothing about Eucalyptus, and haven't been around one for years. Though Googled enough to find it was likely eucalyptus torelliana (now corymbia torelliana) I was reminded of. Here is a link that might be useful: eucalyptus torelliana factsheet

" Wilt is becoming a serious problem in many areas. Also susceptible to mimosa web worm. Self-seeding can produce numerous seedlings. Falling leaves, flowers and seed pods can pose significant clean-up problems if trees are planted near homes. Weak wooded limbs are susceptible to damage from strong winds and ice/snow. Uses: Generally considered to be an attractive but inferior landscape tree. May be used as a lawn accent in areas where soils are poor or alkaline. Avoid planting in areas where wilt is a problem." Even at MOBOT where they have a love for most things oriental mimosa is considered an inferior tree. I see it self seeding all over the place when I'm on the way to the ozarks. Yes it does flower now, but there has to be better choices. Here is a link that might be useful: MOBOT

Whatever it is, you better start removing it. Are all those small things in the final image seedlings? If so, herbicide (triclopyr) or hand pull soon! The larger multistem clump can be managed with a slight variation. Cut off the stems at a foot or so, then immediately paint with full strength triclopyr as is directed on the label. Triclopyr is an active ingredient which is more effective on woodies than is glyphosate, the latter in Roundup & more.

Thanks for the leads. Looking at my tree guides I could only tell it wasn't a pin or burr oak lol. Only had my cell phone with me for pics. Has good resolution but doesn't zoom worth &*$@.Even dorking it up and standing in the bed of the truck I couldn't get any closer to the leaves. Gathered up a couple acorns but who knows which oak in the grove they were from. I'll see if any sprout up in the spring with similar leaves.