Steve, All;
Jeeze, and I get nervous with a hydraulic splitter when someone else has the lever and I'm handling the wood!
Normally I would not pick up cottonwood, but I got a couple of truck loads of cut up rounds for free, and it's so easy to split.
It turns out that in my Quadrafire, it really puts out the heat and it burns totally clean. It won't last as long as madrona, which I save for night time, but it will rekindle quickly when thown in on last night's stirred up embers.
The new emmisions certified fireplaces are more efficient, put out more heat, burn less wood, and have much cleaner stack emmission. The secondary air (or top air) and baffle inside the fire box must be a big part of that. My air control has a spring/timer thing at the 'full air' side for starting the fire, then it sets back to less air to finish burning the wood when it is mostly glowing carbon. It can be adjusted much lower to make the wood last all night, but if I set it that low the windows will soot up.
I've got Fir, Deodora cedar (smells fantastic!), cottonwood (doesn't smell so good), madrona, elm, hemlock, cherry, black locust, and mysterywood (I don't know what it is). They all burn a bit different, and I try to use that to advantage.