Rehabilitation post fire

By Sandy Benson

Rehabilitation following prescribed fire suppression activities in Mount Riverview

After a recent prescribed burn on a Mount Riverview Bushcare site, rehabilitation of several constructed fire containment lines has been completed. These containment lines or fire breaks are used to protect surrounding bushland that are not registered to be burnt. Unfortunately, fire breaks have the potential to create erosion unless rehabilitated by stabilising the exposed soil.

The aim of this rehabilitation project is to prevent soil erosion and reduce the likelihood of the fire breaks becoming new walking or bike tracks. The fire breaks were covered with a base of jute mesh, then native on-site mulch including branches, leaf litter and rocks were spread over the top to blend in with the natural landscape. The Mount Riverview site will be monitored to ensure that the fire break is not visible or subject to erosion due to extreme weather conditions.

Post fire can offer favourable opportunities for weed control and management or can have a negative effect on a site, dependant on the intensity of the burn. In this case, as the fire was a controled burn and not a wildfire, the intensity was low or considered a cool burn. Post cool burns, most plants can re-shoot from their stems due to thick bark that protects the buds from damaging heat, so they can recover rapidly after a fire. Native plants hold their seeds in thick woody fruits or capsules, where they are protected from fire, the fire assists in opening the capsules. When the seeds fall to the ground they land in the ash bed, which is high in the nutrients needed for strong seedling growth. This aids the natural regeneration of the bushland.

Post-fire risks and opportunities

  • Improved access: provides opportunities to control weeds that were difficult to access.
  • Mature plants are killed or reduced in number.
  • Exhausting weed seeds in situ if consistently followed up with weed removal: manual removal or spraying of seedlings before maturity and seed setting can exhaust or reduce the weed seed bank.
  • Mass establishment: fire can be particularly favourable for weed species and a substantial increase of the initial infestation may occur post fire.
  • Cause erosion and subsequent sedimentation of creeks and wetlands.

Post fire weed treatment can be particularly effective and presents an opportunity for a local reduction of weeds. The Mount Riverview Bushcare group has been involved in post fire weeding and monitoring of the site. Access to areas infested with weeds post fire has been greatly increased and has allowed Bushcarers to reduce the number of weeds in the burnt areas.

One of the containment lines post fire and before the treatment
The containment line after rehabilitation