Couple more minor thing to add.
Buck your trees where you drop them. If you drag them through the dirt, it's just the same as running your chain into the dirt and you'll be sharpening or swapping loops every few cuts.
A properly sharpened chain can't be emphasized enough. There is no amount of hp that will make up for a dull chain, all you make is noise and sawdust when a chain is dulled. Spending a couple of minutes swapping out a dull loop will save you hours of grief trying and failing to make a dull chain cut.
While I like hp...
(my ported 181 was a cutting fiend)
...having a saw that isn't too heavy is also a performance issue. If I was falling and bucking trees daily I would have been in shape for such a heavy saw. But for the occasional wood cutting home owner an 80cc pro saw had my back aching by the end of the day.
My next saw will be a 562 XP