Q.Bark on grape vines is peeling off
The bark on my grape vines is coming off in strips. These grapes were planted approx 15 years ago and are well established. What is causing this to happen?

A few things come to mind:
The age of the wood: As the following article suggests, "Older bark cracks from the expansion growth of new bark beneath it, creating the peeling bark that is characteristic of older wood on grapevines". https://bit.ly/1er3KGf
It could also be the result of winter injury as suggested in the following Cornell University article: https://bit.ly/1FAfOy1