I'm pretty positive there is a minimum amount of posts or a minimum time of membership on the forums that you need to meet before you can access the Blog Tree. However, the Blog Tree button should be in between "ACNEWLeaf.com" and "Shop" on the tab just below the forum logo. After clicking on the Blog Tree button, you are sent to a recent blog post feed, and just to your right, there is a "Create New Post" button.
That's funny, lol. You can also subscribe to blogs you like, and I believe you are subscribed to your own blog automatically as well. You get email updates whenever someone replies to a subscribed blog.