I see, that sounds like a frustrating experience! Just so you know, if you bash a tree and nothing comes out, the best thing to do is to move onto the next one! If there's a demon in a tree, it will come out on the first hit. If you're unable to hit the tree, make sure you're right underneath it. Perhaps I should add that to the instructions so it's clearer, I'll have a think on the best way to put it.
Also, the trees that have demons in look different from the others, they're a little spikier in appearance.
I hope this helps!