Create a watercolor clipart of an open book on a white background, with a nature-themed fantasy twist. The book should be filled with imagery that is inspired by the natural world and has a magical element, such as a treehouse in the forest, a magical garden with talking animals, or a river that leads to a hidden land. Use soft, natural colors and loose brushstrokes to create a watercolor effect. The open book should be centered in the piece, with a subtle drop shadow to give it depth.