Help with ring damaged tree please

[CarpeDiemBill]

hi, hoping somebody can help.

i planted a row or laurels a couple of years ago and during the summer, about 4 months ago, i was strimming the grass and caught the base of the tree. I don't think much of it but had a look and somehow it had stripped the bark all the way around about 3 inches up from the base for about an inch gap. A full ring!

A quick google spelt certain death for the tree so I read on and found that you could bridge the gap and it may take.

im not a garden person at all, but I delicately took a small branch, and began the process of bridge the gap. I also shaved the bark of the branch and made thin strips that a place  across the gap. It looked a bit like a Frankenstein job but I had a bridge and wrapped the gap with fresh bark all within about an hour. I then proceeded to wrap it with cling film and taped it up waiting.

it seemed to have survived, I figured it would last weeks but months later it was ok. This week I noticed it was the only tee with yellow leaves, with the exception of the odd area on the row of trees. Fearing the worst I removed the cling film and tape to reveal this.....

I have no idea what it is.

 

i quickly wrapped it again and then pulled some soil onto the base as I guessed they may be roots forming and be hunting down to soil.

 

does anybody have any suggestions or is this a lost cause?