I don't need to tell anyone here that there are better uses for walnut than as firewood.... But, long story short, a friend cut up a black walnut tree that fell in his yard before I could save it. I graciously accepted the firewood The wood has been split and stacked (cross-hatch) since february, and I am now getting around to burning it. Could maybe wait another summer to be fully seasoned, but its pretty well dried-out. My conclusion is that walnut does not burn very hot. It does burn long, and coals fairly well, but not that great in terms of BTU. On the other hand ELM...well lets just say I put ELM right up there with Locust for heat....nearly impossible to split but sure does burn hot...and forever. No smoke, no ash and great coals with ELM. I often see ELM on firewood rating charts as somewhere in the middle...as a medium hardwood, along the lines of walnut. I call foul. Anyone else have experience burning ELM? Its great for heat but such a PITA to deal with. Anyway...great site here...glad I found it. Stay warm.