In one of my attempts to build my auto wood farm, I decided to build it under my mob area warp floor, bad choice A big tree went through my warp and destroyed part of the floor, lool. The power of trees ._.
Damn son. I was trying to stay quiet but I just saw your signature and snorted really loud and woke a few People up this your fault :[
Cap them with half-sized blocks to prevent this situation. Then trees won't grow higher than limit. But it causes their growth rate.
I moved the thing so it will be in open space, thanks for telling me this since my farm has been only making huge trees.