That is a fungus working on the dead wood inside the tree, isn't really infectious to other trees unless they also have dead wood inside and are the same or similar species.
And someone needs to learn to prune correctly - leaving those nubs is a no-no. Branches should be cut to the "branch collar."
hortster

consider that whole part dead...

where will it fall????

if your house.. you have problems ...

otherwise healthy tree.. do not magically pic up things in the air ...

so the only real issue.. is whether your tree is healthy ...

ken

Thx for the feedback, glad to hear we will be okay. Its streetside and pretty small (15ft) so no worries on it falling on our place.

Thx for the feedback, glad to hear we will be okay. Its streetside and pretty small (15ft) so no worries on it falling on our place.