I have found a feeding ground of Mulberry trees that were taken down. When cut with the saw I see kind of a milky sap coming out. I have heard great things about mulberry and I assume it is worth the effort. I have had a lot of success with Oak and don't want to stray too far from the BTUs and burn times. Is the mulberry worth the efforts? FYI the place I am getting it from is literally across the field from me.