I suspect it's an availability thing. Folks who actually live in the mountains burn what's available, which means conifers. (We don't have hardwood forests per se out here.) Smart folks have flues with outside cleanouts so they can more easily clear the creosote.

In the Pacific Northwest the foothill alder and maple burn well and in California we haven't yet mowed down all our oak but are rapidly working on it. I usually buy almond, which burns hot and clean and as an agricultural product is actually renewable. It's misreable to split, though!

Cheers,