Gnawing/Nighttime teething branches

[Kristal]

Are there any trees whose bark is NOT safe to give to squirrels? If yes, what are they called, and please give photos, if possible.

[wheezer]

I don't know of any but if you have doubt about a certain tree, maybe you could list it here to see what others think. Or just stick with oak, maple, fruit trees, walnut etc:)

[Kristal]

Well, that is the thing. There are many trees that I don't know by name...