One other thing that we can do with The Monolith, is watch it decay. Even this can be an interesting feature, and something to study to help people better understand how a tree that is dying breaks down. As this tree no longer has a need to support its internal system; that in turn helps support its external elements such as leaves and 'fruit' (acorns), and is suffering from an internal rot it will eventually start to break down further, until eventually we will have to remove the bird & bat boxes, and the rest of the tree itself.

How long will this take? Well, that's only something we can find out by watching it. It could be many years, and will depend on any conditions it is subjected too (such as the flooding ground, new exposure from lack of leaf cover, frost, sun, pollution and more...!
(Looking at some of the other monoliths in the Square may help give some idea though).

Of course this tree may surprise us, and... come back to life.
Well... sort of.

It is entirely possible new growth might start appearing on the tree. However, this doesn't necessarily mean it will have recovered. New growth can still occur in a dying tree. This is likely because parts of t he tree are still living, but because the tree no longer has a canopy of leaves to help sustain it, the still living parts may therefore put out shoots and buds as a way of trying to counter-act this. But that may not be enough...

It'll be a slow process, and will only work on a small scale, AND still have the encroaching rot to work against, but it is certainly something worth keeping an eye on as an ongoing observation experiment, and chart any progress it makes.