Trees shall be classified as follows, and the requirements pertaining to each class of tree shall be as provided in Articles V, VI and VII herein.
A. 
Class A: trees with a diameter up to and including 10 inches.
B. 
Class B: trees with a diameter of more than 10 inches and less than 20 inches.
C. 
Class C: trees with a diameter of 20 inches or more.