They are called Wayfinder trees because of the polkadotted spots along the bark.
Dragonborn have found that no matter the dominant Dragon in the area, the spots on the bark have a different color - similar colors line up on different sides of the tree in columns of sorts. hey have a peculiar trait; if you follow the direction that a line of colors point to, you will make it to a different Dragon's domain.
The bark is blacker; little gashes along the bark aglow with the colored magics of the dominant Dragon. The branches uptop would tell you the kind of Dragon.
- If it were ice, those branches would be pure ice growing in distended shapes.
- If it was poison, the little knots you see along the branches would be oozing poisonous sap a neon green color.