When I lived in Colorado in a house with only wood heat, it didn't take me long to learn to bypass cottonwood and elm. Hard to split, burns poorly, stinks and you can durn near freeze to death on the heat it puts out. Not to mention tons of ash to clean-up. The elm and cottonwood both burned thier best after 3 years in the back of a dry barn, and that wasn't very good.
I was fortunate to have access to lots of dead aspen, pinions, junipers, cedars, scrub oaks, ponderosa pine and coal. The most seasoned the live stuff ever got was about a year and did fine, except maybe for a little extra creosote cleaning.
