goats and my orchard

I am getting two Nubians in a couple weeks, I was planning to keep them in the orchard, but someone has advised against it because they said the goats will kill the trees from eating the bark. Is this true? What are other people's experiences/advice?

Also they are yearlings that have always been fed goat feed, so are they even going to recognize the blackberry bushes etc. as food?

Thanks!

Unless the trees are big enough that the bark is rough and scaly, and tall enough that the goat cannot rear up, or put its forelegs up on the trunk and reach lower branches, you are asking for trouble! Goats are nosy and smart.....and they will try new things!
A few ways to proceed would be to stoutly fence a circle around each tree....bringing with it the problem of being able to access the tree yourself. A goat will worry with a gate or closure with more persistence and more intelligence than you can imagine. I had success on one farm by taking old metal barrels, bottomless, and setting these around each tree up on glass jugs laid on their sides, or stout pieces of plastic, and then hooking this to electric fence so that the entire barrel was electrified! But, as the trees grew, the barrel was stranded there forever. It is possible to train goats to respect a single strand of electric fence, by means of baiting it with tags of foil with something yummy on it like peanut butter. But a new or desperately hungry one will always push the boundaries!

Dogs like to chew on bones just because it fun, not because they are hungry.
GOATS like to climb fruit trees and nibble, just because it is fun. They will also work as a group to mount a big tree.

Goats without an effective means of control are a scourge to the land! Like the others have already said, they will first defoliate every bit of the tree they can then will debark them. Goats also love to climb, have seen them get on all kinds of buildings, equipment, etc.. Knew a guy asking very similar questions before he got several young goats, he didn't quite understand the meaning of a "good fence", a couple of weeks after he brought his goats home, he went out to investigate a strange noise, he almost cried to find the goats playing king of the hill on top of his new farm truck. Goats can be very useful but have to be controlled.