After a certain incident, I'd like to point out that one should be very cautious when using the TreeAssist(auto-chopdown) plugin; if you're careless, a tree of the right(wrong in this case) type can and will chop down any structure of the same log type along with it if it's too close!

With that said, either start the chop from the second portion or be very careful about where you place your trees.

Be safe, and may your haul be bountiful!