Conservation of trees during land development process; Planning District 8; minimum tree canopy or cover percentages requirements after development. Allows any locality within Planning District 8 belonging to an eight-hour nonattainment area for air quality standards to require, by ordinance, that a subdivision or development provide for the preservation or replacement of trees on the development site such that the minimum tree canopy or cover 10 years after development is projected to meet specified coverage criteria. Under current law, the criteria apply to tree canopy coverage 20 years after development. The bill also allows such localities to include in their tree canopy ordinance reasonable provisions preserving trees of outstanding age, size, species, beauty, or other special significance.