I'm gradually trying to get invasives removed from our property, replacing with natives to this area. I believe this is a tree seedling, and I think it's white oak (which would be good for this area). Can anyone confirm or advise what it really is? Can I safely move it (because I can't really leave it where it decided to grow). Larger, close-up image click here.
That is a White Oak, Quercus alba.
You can move it now, if you take it with a very large root ball, and water it well. Even at that size, It will have a large well developed root system. The ball should be at least 18" deep and wide, and without cracks. Plant it in loosened soil in a hole at least a foot wider than the root ball.
I have had the best success with transplanting oaks in the fall after leaf drop (or leaf dieback). I take a sharp shovel and dig out the entire root system, and carefully loosen all of the soil and shake it out. I then plant it in a large hole by removing enough soil to contain all the roots with 6" clearance at all points. I then carefully fill in around the roots with screened topsoil, being careful not to leave pockets. I tamp down as I go so there will be little settling.
After planting, I water at 1/2 gpm for 15 minutes or so, until the soil is quite damp all the way down. This way of planting can be done in less than twenty minutes per tree with practice. The trees have always responded well to this and get off to a good start.