I like 6-8ft as well. And I really like cedars... transplant a few hundred out of our pasture each year! When we first started doing habitat management on our farm we burned every grassy brome area we could thinking prairie grasses would "magically" show up and become this thick prairie... not the case. In the process of burning we burnt up 100s of awesome 6-15ft cedars and just wiped out some awesome whitetail habitat and were left with even healthier brome fields that now had a few spots of prairie that was so thin it couldn't hold a single deer. Anyway, what I mean to say is Daver hit the nail on the head stating to be careful if you plan on burning near your cedars! We leanred to pick where we want cedars/trees to get established and where we want prairie. One gets fire and the other we keep fire as far away as possible (this doesn't mean we won't burn mature timber to regen some oaks thought)