Whatever caused it (sun scald, frost crack, mechanical damage), it looks to me like there is callus tissue forming, which means that it is beginning to heal. From the size of the wound, it may take more than one season. I would remove the loose bark, which will clear out the ants and the earwigs and allow you to see it healing better. Don't put any paint or anything on it - just let it heal itself.

Thanks for the reply. I pulled off some of the bark and it appears there is some sort of growth that is forcing the bark to split. Any idea what this growth is??

That growth is the callus tissue that I was referring to. It is not forcing the bark to split but rather trying to grow over and heal the wound.

Not sure your zone...but many trees suffered from this harsh past winter with trunk bark splitting. (Had it happen in my own back yard. And the local nursery said they've seen more this year than in years past over the harsh winter we just had.) Let it be...it will heal on it's own accord is what I was told.

My weeping willow tree is 15 years old and this year the bark is falling off and I have branches that are dying. And only some them have leaves on them..Can you help? Called a lawn and tree service and they wanted 900.00$ to try and fix it..no grantees.