charles, check out what the fallers are using. up here we run our saws with 36" and 42" bars on 'em.
big trees up here- and in the old days when men were men they used to run the old stihl 090 with a 6' bar and two powerheads on.
we have cedar up here that is still 6 - 11' at the stump, i think our biggest spruce here is 17' but will have to just verify that- but i have personbally seen them in the 10 to 12' range.
the fallers here swear by them both, and its all personal. what i do notice though is that all the young bucks love the stihl- faster , maybe slightly tougher machines- maybe!!- i run a stihl, and the company i work for only runs stihl, however a lot of the older fallers are switching over to husky- better vibration dampers- kinder on the hands- dont get "white finger" as much.
good luck
ps. learn a little about falling a tree- befor you go out there and hurt/kill yourself.
i know of a lot of dead fallers!!!!!!!
it happens so quick.
pm me if you need some more info- would be glad to help!!