The artist rendered the the art with watercolors. I like the different perspectives that he uses, for example when looking down on the tree. I like how he draws the words for the name of the tree out in a decorative way.
His style has a realism to it, a simplistic way about it, but yet there are details too. Maybe you'll come up with a term for that, but I haven't yet. Maybe it could be a realistic simplicity that is enchanting? Email me if you have a real term for that.