When building or remodeling a home in Austin, Texas, one of the important regulations the city requires you abide by is the Tree Ordinance. Protected trees and heritage trees impact how and where your house can be built or changed. This video discusses the difference between a protected tree and a heritage tree, how to measure them, and how to calculate the half critical root zone.
City of Austin Arborist Page: http://www.austintexas.gov/department/city-arborist
Austin Critical Root Zone Regulations: http://austintexas.gov/page/tree-natural-area-reservation-codes
Austin Protected Tree Species: https://www.municode.com/library/tx/austin/environmental_criteria_manual/apxfdecatrsp#TOPTITLE