Evil Tree Concepts

Inspired by a series of educational videos that are available on concept artist Trent Kaniuga's Gumroad page, I whipped together these evil tree concept pieces to try out new techniques and just generally have a bit of fun with some especially whimsical high fantasy. The animated tree is a wondrous fantasy trope, and might evoke trees such as the Deku Tree from the Zelda games or the Tree Boss from many Kirby games. For me, at this point, I can't help but think of the first boss from the 1990 Sega Megadrive classic, Mickey Mouse: Castle of Illusion, which was one of my earliest gaming experiences.
At any rate, I'm constantly striving to improve, so please do leave any and all constructive criticism and feedback that you might have in the comments below. :)