Tree Risk Assessment Qualification (TRAQ) Practice Exam

Live crown ratio measures how much of the tree’s height is occupied by a living crown. It is defined as crown length divided by total tree height. Crown length is the vertical extent of the live crown along the trunk, from the top of the crown to its bottom, while total tree height is the distance from the ground to the tree’s tip. So the best definition is crown length divided by total tree height, often expressed as a fraction or percentage. Dividing crown length by crown width describes a different concept—the proportion of crown height to crown spread, not the canopy height relative to the tree, so it isn’t live crown ratio. Using trunk diameter instead of height mixes a girth measure with canopy length, which isn’t the intended ratio. Root depth over tree height looks at below-ground structure, not the canopy.