Crown position and light exposure classification - An alternative to field-assigned crown class

Crown class, an ordinal tree-level mensuration attribute used extensively by foresters, is difficult to assign in the field because definitions of individual classes are confounded by ambiguous references to the position of the tree in the canopy and amount of light received by its crown. When crown class is decomposed into its two elements-crown position and crown light exposure-field assignments are more repeatable, and crown class can be assigned by algorithm with the same degree of accuracy that it can be estimated in the field. Replacing traditional crown class with the two proposed alternative variables yields more specific information about each tree. Crown position and crown light exposure add information potentially useful for modeling and other applications.