Acacia Removal

Reducing wildfire risk and protecting rare plant habitat in Old St. Hilary's Preserve.


Acacia, listed as a noxious weed by the state of California, is highly flammable, and creates an environmental monoculture. This non-native tree has begun to spread in Old Saint Hilary’s Preserve. This project aims to remove the largest, most dense stand, situated on a steep slope directly below neighborhood homes.


  • Reduce fire fuel adjacent to a residential area.
  • Protect habitat of the Tiburon jewelflower, found only on the Tiburon peninsula, as well as other special status plants.
  • Apply minimal herbicide based on critical use principles, with the goal of getting to zero.


  • Fall 2018: young Acacia sprouts hand-pulled by staff and volunteers
  • September 2018: Marin County Fire cuts mature stands of acacia. Stumps carefully painted with aquatic-approved triclopyr-based herbicide.
  • Spring 2019: Pile burning
  • 2019, 2020, and 2021: Acacia sprouts spot treated as needed with aquatic-approved triclopyr-based herbicide.
  • Post 2021: Remnant populations managed by manual management methods.