Cats shredded cherry tree bark

[BarleySugar]

My fan trained cherry tree is 3 years old, and never been used as a scratching post before. Mine have an indoor one they use, as well as the fence posts and the trellis post.
This morning when I was looking around the garden I noticed the trunk has had a good deal of bark scratched off at the front (the back is against the fence). It has been done in the last couple of weeks I would think. I suppose the damage is about 6 inches long. I have put a guard up so whoever it was cannot get to it now, but the trunk has exuded some sap, and I was wondering if anyone has any advice. A google search says to paint with indoor latex paint? It was a site from the USA.

[Nicos]

I used to have a flowering cherry which was used as a scratching post, and it just healed itself but with big knobbly scars.
I can imagine if it's used too often then it might well die?

I'd probably buy a tube of sealant used after pruning trees- can't remember what it's called ( it's in my shed in UK) but the tube looks like shoe whitener with bristles ( instead of sponge) at the top.
I had an apple tree which had been damaged by a support post rubbing it over a period of 2 weeks during a period of very strong winds- and it sealed the area wonderfully ( dries hard).I suppose it depends on the size of the area involved.

[BarleySugar]

Thanks for the advice, I couldn't get out today, so I was hoping someone knew what to do . I might be able to get to the garden centre to have a look tomorrow, weather permitting.
It is quite a big section, good job it's against the fence so they couldn't do it all round. The tree was pretty expensive and we'd just started getting a few cherries last year.