It is probably the drought you had keep it really well watered.

This happened to mine last year and all the leaves had gone by mid July. I watered and watered it and it came back fine this spring. I did some research when this happened and apparently Rowan roots can stay in place and not reach in to the surrounding soil thus suffering in a drought? Last year was the first time this had happened to mine (10-12 years old) I have watered it in the drought this year and its stayed ok so far.

Leave the hose trickling at the base for 12 hours, or overnight.

thank you to all but i think its more than the drought

i have taken a few pictures i will try and up load them thanks again

That certainly does not look like a healthy tree trunk! No idea what to suggest you do though!

Ah, now you didn't tell us there was damage on the bark! Possibilities are some kind of canker, if the black areas are seepage from the tree, particularly if the area shown on the trunk is soggy, or fireblight's a possibility too - if you can remove one of the smaller stems or branches which has died back, peel back the bark, if its fireblight, you'll see a foxy red discoloration in the wood beneath. Either way, if that area at the base of the tree is soggy,and it spreads, you'll need to get it taken down before it falls down.

thank you someone else mentioned fireblight any cures for that ??

No, there is no cure, and you must not plant anything from the Rosacea family again in that spot, if that's what it is. Plants in that family include roses, prunus, photinia, pyracantha to name a few. Its still a notifiable infection in some parts of the country.