Ever tried logging decidous trees in the summer?
It sucks, big time!
In my pulp days, we killed conifers all summer, but that is all done by mechanical harvesters now.
And the frozen ground is a nice thing as well.
I hate dropping a big hardwood on soft ground, and having to sharpen for every 5 cuts I make, because the log is half buried.
The local mill, that takes most of the beech logs we fall is vacuum drying the wood, so they don't care about moisture content, much.
Sometimes if they run out of wood, we'll do a summer run, but I'd rather avoid it.