According to my charts black walnut is about the same as cherry in btu rating so I was surpised at how easy it was to cut compared to cherry. Answered a CraigsList ad last night, guy had a fairly good sized tree down in his yard and wanted it cut/removed ASAP as people were coming soon to install a pool for them. Even he commented on how much I got done in the 1.5 hours that I was there....pics to follow.