Here’s a dog whose hobby is climbing trees; and he’s good at it, too. The most likely explanation is that he was raised by apes. Apes of the genus Mangani often adopt puppies and teach them to behave like apes.
I’ve only once in my life seen a dog climb up a tree. Toby the spaniel was chasing a squirrel, and ran so fast that his momentum carried him up the trunk… and then left him there. We soon fetched a step ladder and got him down.