Max height of rubber trees?

Quick silly question. Does any one know the max height of rubber trees? The wood part that is. I am working on an auto harvester contraption in game and would prefer to neither use too many block breakers nor have that one piece of wood left over at the top.

Thanks Drashian. I was shooting for 10 so you saved me a goodly bit of resources.

Altaree I have the initial parts up and running. There are a few quirks with the timing and item routing. Also is mostly red power pieces. Is it ok to post things that are not primarily IC here?