I've tried to add the class that misty world trees use but only some leaves work while others do not, This may be an issue as the leaves on the trees are coded differently (they act like dynamic trees). If there is a way to change this if it isn't a bug please say.
I have also put the images for it below:
(the leaves on the ground are placed ones)

This is also the case for the dirt and grass blocks but they never work with the features.