Hi. Can this red squirrel be damaging my tree? Could it kill the tree? Are there any actions I can take to eliminate the squirrel? Thanks very much
Typically, hollowed out portions of tree are signs of previous damage. These are not, generally, regarded as harmful unless they collect water and rot.
If a squirrel is living there, then it is probably a place that remains dry.
Should you want to keep them away from the area, there are a few ways that you can do so.
This article will help:
https://www.gardeningknowhow.com/plant-problems/pests/animals/squirrels-damage-to-trees.htm
arborist wants 700 per tree to treat appaly fortiphite and spray but not with what
Unfortunately, most treatment needs to be aimed at prevention. Once infested, it becomes near impossible to treat.
https://www.gardeningknowhow.com/plant-problems/pests/insects/preventing-ambrosia-beetles.htm