That's where it is. You will find 
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>420 Cherubi
Tree Location: National Park
Accessed Through: National Park
Requires: Rock Climb
The tree that Cherubi is in is located within a cliffed area within the National Park. Like the other areas in Johto, you require the use of Rock Climb in order to get it. In the north east of the park, you will find a break in the fence and can go by the trees. Near this opening, you will find the cliff that is scaleable. Go to the top tree and use Headbutt and you'll find the tree.
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