Please forget that idea immediately.
(Unless you want to slowly kill your trees, have them become unstable, brittle and generally dangerous, of course.)
There are two types of mushrooms that grow on trees.
- The non-parasitic ones that consume already dead plant material. If they grow on a tree, it was already damaged at this spot and the mushrooms are just digesting the rotting material. Note that we discussed that mechanism already in the comments of your „oyster mushrooms in plastic boxes“ question.
Those mushrooms won’t colonize a healthy tree and if you put plugs into them, they should either die or you as the interfering human effectively started to kill the tree because you damaged the tree which may cause local decay.
- The parasitic kinds that digest the lignin (causing white rot) or cellulose (causing brown rot). These can actually kill a previously healthy tree if the spores can find a spot to grow, e.g. a small damage.
Wood decay often remains invisible to the casual observer. The tree may look fine, perhaps with a few dead branches, but be already unstable and dangerous. Every responsible gardener will make sure that the trees in their care are healthy and remove branches or trees that are seriously affected by parasitic fungi to prevent them from falling on buildings, other structures or - even worse - humans. (An infested tree in the wilderness is different. Let nature take its course there.)
So to sum this all up:
Either the plugs won’t grow in your trees (but the damage to the tree will be done, possibly leading to other infections) or you will be killing the trees. Note that the mushrooms have to “eat“ something, which will be the wood of the trees in question. Mushrooms cannot do photosynthesis, they require organic material to digest.