No county tree permit is required in unincorporated Williamson County, TX. Check your address to confirm you are outside city limits and see what still applies.
Texas counties have no general power to require a tree permit on private land, so unincorporated Williamson County has no county tree permit. Deed restrictions, HOA rules and utility easements can still apply. If you are in a city's ETJ, the City of Austin tree ordinance does not apply there.
Texas law: cities cannot charge a tree mitigation fee for a tree under 10" at an existing one- or two-family home you live in (Local Gov't Code §212.905, HB 7, 2017). Since 2023, landowners can petition to leave a city's ETJ (SB 2038), so ETJ lines change; we read the live City of Austin jurisdiction map.
Official sources: statutes.capitol.texas.gov/Docs/LG/htm/LG.240.htm · austintexas.gov/development-services/city-arborist