However, the City of Williamsburg may require at 10 years the minimum tree canopies or covers set out above.
"Tree canopy" or "tree cover" includes all areas of coverage by plant material exceeding five feet in height, and the extent of planted tree canopy at 10 or 20 years maturity. Planted canopy at 10 or 20 years maturity shall be based on published reference texts generally accepted by landscape architects, nurserymen, and arborists in the community, and the texts shall be specified in the ordinance.
Va. Code § 15.2-961