Well, the first photo is taken from quite a distance but the canopy looks healthy. Is that the case? Regarding the trunk, the mulch is pulled up too high around it. The root flare should be visible. Once the mulch has been pulled away you should have a clearer idea of what is causing the pile of material. Is that soil or sawdust? Btw, the cultivar name is ‘Kanzan’.

socalnolympia-not necessary to put me down. I'm 80 years old and in poor health!

floral-the mulch is about 2'" thick. That is sawdust with a lot of ant activity.

FWIW I have compact weeping cherries that have had huge cracks for many years so it’s not necessarily the death knell. If there’s a way to prevent further damage from them I’d love to know.

David, you may be interested in reading a new biography about the English plant explorer Collingwood Ingraham who collected and saved many Japanese cherry trees from extinction in Japan after reintroducing them from his garden in England. Floral, you may know about that garden which I believe is being restored. I found the book fascinating and learned much about the tree and its cultivars, including Kwanzan.

https://www.japantimes.co.jp/culture/2019/02/09/books/cherry-ingram-homage-british-savior-japans-cherry-blossoms/#.Xu8jl8Bq3Ds

I imagine this is the book in question. Note it refers to ‘Kanzan’ rather than ‘Kwanzan’. Note too Cherry Ingram’s hatred of it. https://books.google.co.uk/books?id=6mhkDwAAQBAJ&pg=PP103&lpg=PP103&dq=cherry+ingram+kanzan&source=bl&ots=Kx0Busqvnj&sig=ACfU3U2w0TNlgVEjlixHLVWjfbIfftlA8Q&hl=en&sa=X&ved=2ahUKEwiknpms1ZLqAhU7QEEAHahzDpMQ6AEwA3oECAMQAQ#v=onepage&q=cherry%20ingram%20kanzan&f=false

I was not going to mention that, Floral...

There is a 12" long vertical crack in the ruck where the ants come and go.

Start by getting the mulch away from the trunk.

The mulch layer becomes purely secondary in the face of that huge sawdust pile indicating significant insect activity of some kind. Borers? Carpenter ants? Impossible for anyone here to tell, without additional photos showing something like a nest entrance or a series of individual holes in the trunk.

An ant trail leading to and from the tree would be a definite hint.

I will send more pictures. Is there any way to stop the ants. They are inside the tree

Search the web for "how to kill carpenter ants"

Yes, the mulch is secondary at the moment. But as I said above, to see what the ants are doing the mulch needs to be pulled away. And if the ants can be fixed then removing the mulch still needs doing.

imo .. its an overly mature .. short lived tree.. past its prime.. it might not look it.. but it is ... in tree time.. it might take 10 years to die.. or get so ugly that you make it die thru removal ... its still marching down that road ...

even if you get rid of the interior bugs.. there is no way to 'fix' the interior damage they have already started ... which is eventually going to lead to interior rotting and decline ...

the key here .. is that it APPEARS that if it were to fall down.. its not going to damage anything ... unless its closer to that shed.. than it looks ... if it is far enough away... you can try to fix it.. and otherwise enjoy its decline ... its all part of nature ... so why not watch and learn ...

in the alternative.. if it were overhanging a house.. or something precious.. i would suggest removal in the near term future ...

i will repeat what others said... if you get 20 years out of this type of flowering cherry ... thats about it ... and then its all downhill from there ... we cant fix that ...

ken

It was planted in 1994! I'm 80 years old so the timing is perfect!