A Numerical Rating System for Crown Classes of Southern Hardwoods

A numerical rat ing system to del ineate crown classes of southern hardwoods is described. The system is bused on four cri ter ia: (I) amount o f direct sunlightfrom above, (2) amount of direct sunlightfrom the s ides, (3) crown balance, and (4) relat ive crown size . The total point value assigned places the tree within one o f the,four crown classes . The rat ing system can be used to train inexperienced hardwood foresters and should give experienced,foresters a bet ter grasp o f those fac tors important in hardwood crown c lass i jcat ion . Time required to evaluate a tree varies by tree, by stand condit ions, and by observer, but experienced users o f the system can easi ly rate most trees in 30-4.5 seconds . The rat ing sys tem is part icular ly useful in s i tuat ions where an individual tree appears to be borderline between two crown classes. For researchers, the system provides: (I) an expression of individual-tree crown characteristics, and (2) documentation qf changes in crown posi t ion and condi t ion. In two tes ts comparing the numerical rat ing sys tem with the convent ional crown classijication system, use of the rating system consistently improved the ability of participants to correctly identib crown classes. Dominant and suppressed trees were the easiest to assess with the numerical rating system, whereas codominant and intermediate trees were the most dijj%ult. Agreement between part icipants and experts in ident$cation of crown classes increased with the level of the participants’ forestry knowledge and experience. In one test , a group o f part ic ipants at tending a cont inuing-educat ion hardwood shortcourse , but wi th l i t t le to moderate hardwood experience, correct ly ident i f ied the crown class o f 78% o f the trees after only I hr of training. South. J. Appl. For. 25(4):154-158.