Definitions in Subtitle 27 of this Code (the Zoning Ordinance) and Division 2 of Subtitle 25 (the Woodland and Wildlife Habitat Conservation Ordinance) shall apply to this Division and shall be supplemented by the definitions in Subsection (b) of this Section unless otherwise noted herein. The following terms used in this Division are defined as follows: Tree canopy: The land area under the dripline of an existing tree or group of trees or the amount of credit provided for planting trees of a certain species and certain size at time of planting in conformance with the worksheet provided in the Technical Manual. Tree canopy coverage: The combined area measured in square feet of the tree canopies of existing trees and trees planted in conformance with this Division and the Technical Manual. Tree canopy coverage requirements are measured using a percentage of the gross tract area.