I have so many chewing rodents and rabbits at our farm that every tree has to start in a tree tube. I did try some in chicken wire, but the wind beat the heck out of the branches that grew through the wire and sometimes damaged the bark.
If you do not have a deer problem, then you can buy long tubes and cut them down as needed. I purchased 5' tubes and cut a lot in half for some tiny oak seedlings. It is easy to drill holes as needed for your zip ties.
I think you can now purchase 6' tubes. You could probably cut those into four pieces that would be tall enough to deter rabbits.
I use 3/4" PVC tubing for my stakes. Buy the 10' sticks whenever there is a bulk sale at the big box hardware store. They flex a little in the wind, so your growing tree will start to put on some mass at the root collar, instead of growing up spindly.
P.S. I have had multiple trees where the main leader died due to animal chewing, drought, or a very hard freeze. At least 50% of the time, I would get some water sprouts growing out from the base of the trunk, or even from the roots. I now have several 6-8' trees that grew from such humble beginnings.
My advice is to keep nurturing the damaged trees a little, and see if they can bounce back from the stored energy in their root systems.
