Oak bonsai

I have been helping around, clearing a piece of "forest", and I found an oak tree which have been cut down earlier. It was sawn off at about a metre height. And the wound was not much to look at. I guess it has to be cut down further and worked on. Its alive, and have grown some new twigs down the trunk. The trunk is pretty straight. Some of the new twigs have died back. The tree is growing a place where it gets mostly shade.
Im a bit afraid that it will get chopped down while im not there, like too many others this summer/autumn.
Can I dig it up now, and plant it in a big container, in mostly cat sand, hoping that it will live untill spring, and maybe get some new few roots before the winter?
Or shall I wait and hope that it will survive there untill spring? I must say that there have been some frost now during nights too.
I havent inspected thoroughly how easy it is to dig there, but I usually get it done.
I like big trees, and I normaly doesnt find trunks that have been cut, that doesnt just rot down in 2 years.
If I were so lucky and get replies today, I will dig it up now.

Thanks, Storm.

Hello Storm. If you have serious concerns whether it will be there in the Spring, then collect it now. Lots of people collect this side of the year. Nice big rootball if you can.

Yeah, take a big rootball and get into the ground. I think that what you want to keep in mind is try to disturb as little root as possible.

Thank you both.

Okay, it has been dug up.
I must say, it took some beating. I had some major problems sawing over the roots. The big root that went away from the underside. Dont know if its the taproot, was about 8 inches thick. I had to use a metal pole and quite a bit of force to be able to get to it. All I can do now is hope. Dont know if it will make it, but it was worth the try. Ill post a few pictures. They arent any good, since its very dark here now, and was for most of the digging time.
It took me 4 hours to get the tree up..

Here it is when I arrived home. As you can see, not much roots left..


In its new home.


And my hand as a comparison. And I know my little finger is bent. I think it has a nice trunk.

And here's one of the whole tree. If it makes it, Im planning in a couple of years to reduce the trunk about 50% or so.

Since an oak preserves most of his reserves in his taproot I hope you can pull this one through. Here in the Netherlands most oaks dy when you dig them up in summer.
The best time to dig them up is spring, just before the buts are goiing to swell.

As I am preparing to get a similar tree soon.. Any news on the survival of this one?

I found a really cool tree. the first year I dug a third of the roots. The second year I dug another third. The third year I dug the final third. The next year I went to collect and found a parking lot. -As told by my instructor