Question

If so what are they and what do they do?

Answer 1

There is a tree glitch in Giant Chasm where you can walk through some trees. It's up in the top left.

There are some more listed on Bulbapedia here including a surfable tree, grass tile on which you cannot encounter Pokemon, mail glitch that makes ability text disappear, duplicate N, and a PWT glitch.

Comments

That isn't a Glitch. They are called Hitten Grottos.

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LOL This is just soo wrong

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Actually, no it's not a hidden grotto. I added a picture to the answer to illustrate.

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Thanks!

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yeah,i was switching the summary 2 cobalion,then at the last moment emboar's ability description wasnt there...

Answer 2

You can surf in a tree at Pokestar Studios; the one at the rightmost and top a bit.