i wonder about this too. my sawyer and woodlot manager is adamant about harvesting only windfall and standing dead timber. some really nice trees do come down on their own. i just finished with a timber today from a white pine that came down in a big storm here in 2006. part of the same project is cedar that this fellow sawed from standing dead cedar, drowned in a beaver swamp. also very nice timber. it's interesting to think that the timber harvested will result in
both the work you're about to do and the quality of the forest left standing.
that said, there's a massive healthy tamarack tree on the property here that would make perfect sill logs. it sounds solid when hit with the back of the axe. but i'll cut down the dead spruce next to it first. it's a lot to take a living thing into one's responsibility. maybe if i were a better framer... but as is, the tree stands up taller and more sure on its than what i'd be making- check it out how tall they are!
this is right on- some trees sound solid in the heart-
cutting trees for shingle-making 
