This and that article about the 16 year old that got arrested for cutting down a historic tree makes me wonder if there's a way to uncut down a tree. Like using grafting and some kind of tree steroid
It's a bit like reattaching a penis. All the tubes are very particular in what they were connected to, so even if you graft it back on you cant direct all of them to reconnect the right way
The closest thing to what you're talking about is grafting, but that's a specific thing that only works on certain species and I don't think can "glue" two entire halves of a tree back together, maybe just a branch at the most if you're very careful and lucky
It's why if you plant a seed from a random apple from the supermarket, you're very probably not going to get a tree that produces that apple. Most commerical fruit trees (including ones from your local garden centre) tend to have a bottom half that's hardy and resistant, and then a top half which was "glued" on that actually provides the fruit you want. The bottom half controls the genetic material in the seed, but the top half controls what the fruit will look like.
On the other hand, you can totally glue a snapped cactus back together, provided it hasn't been too long and the two halves aren't too damaged.
Well the other bit about apple trees is that they exhibit extreme heterozygosity which means they need the genes of two trees to be combined to make viable seeds, and the genes of their offspring are chosen randomly.
So they're like people, the kids might exhibit traits of both parents, but they're not clones. Typically if you plant apple seeds, if they are fertile and sprout, the offspring will make apples that are different from both parents. In most cases, these apples aren't desirable, as there are only a few dozen apple varieties on the market against untold millions of possibilities.
Our neighbors cut down all the trees on their side of the property line, but its been about 2 years now and we've got our privacy back because all the stumps sprouted.
There is a thing called Coppicing or National Trust Link where the stump shoots off and grows new trunks from there. Its not exactly the same and some trees are better suited for it than others.