I agree with the above poster though - I one hand my 200t pretty mcuh 80% of the time while in the tree and every climber I've ever worked with does too. You do see guys straight out of climbing courses and greener than the trees they work on two handing every cut, and doing every other thing by the book too - 2 or 3 tie in points, 2 handed saw use, lowering every branch by rope etc. It is safer, no doubt... but then, those guys take 10 x as long to get a job done ;-)
There's no question that 2 handing a saw is safer than one handing. But then, if you use a saw safely you've got a pretty good margin there even one handed. If you've go a good understanding of the forces in play with saw work then you're ahead a good ways. I think a lot of guys state side are running 14 or 16" bars on their 200t's, and reaching *right out* and cutting with the tip, and when undercutting obviously they are well into kickback territory. I run a 12", wont use the tip or the push side of the saw one handed, only 2 hands for those ops. I do must pull cuts one handed though.
Shaun