District of Columbia Code Division I. Government of District. § 8-651.02. Definitions.

(1) “Circumference” means the linear distance around the trunk of a tree, when measured at a height of 4 1/2 feet.

(1A) “Critical root zone” means the area of soil within a circle circumscribed around a tree's trunk using a radius, measured in inches, determined by multiplying the number of inches in the tree diameter, measured via a method determined by the Mayor, by no less than 18.

(2) “Director” means the Director of the Department of Transportation.

(3) “Hazardous tree” means a tree that, in the opinion of a certified arborist, is defective, diseased, dying, or dead and should be removed; poses a high risk of failure or fracture with the potential to cause injury to people or damage to property and should be removed; or is causing damage to property or structures that cannot be mitigated in any manner other than removal of the tree. In any case, the Mayor shall have the authority to determine that a tree is not hazardous.

(3A) “Heritage Tree” means a tree with a circumference of 100 inches or more.

(4) “Public parking” means that area of public space devoted to open space, greenery, parks, or parking that lies between the property line, which may or may not coincide with the building restriction line, and the edge of the actual or planned sidewalk that is nearer to the property line, as the property line and sidewalk are shown on the records of the District.

(5) “Special Tree” means a tree with a circumference between 44 inches and 100 inches.

(6) “Top” means, as defined by the latest edition of the ANSI-A300 pruning standards, the unacceptable act of tree pruning resulting in the indiscriminate reduction of the tree's crown leading to disfigurement or death of the tree.

(7) “Tree Fund” means the Tree Fund established pursuant to § 8-651.07.

(8) “Tree Preservation Plan” means: