n. The vertical height on a section of a tree bole that has been scorched, burned, or reduced to charcoal.
Char is a general term referring to an object that has been blackened by fire, and char height refers to the vertical distance from groundline to the highest point of blackening on a tree bole. It is usually highest on the uphill side of the tree or the opposite side from the direction of maximum spread. The degree of charring may change along this distance. Char is usually deepest near the groundline and becomes lighter higher up.
Several studies have shown char height, or relative char height, to be correlated with post-fire tree mortality (see Dixon and others 1984; Wyant and others 1986; Regelbrugge and Conard 1993; Beverly and Martell 2003; Hély and others 2003; Thies and others 2006). Relative char height is the maximum char height as a proportion of the total tree height.