Slashing and Mowing

Slashing and mowing of grasses is commonly used in urban-rural interface areas, with strips (generally 10 - 30m wide) maintained near assets as well as roadsides

Grasses are generally maintained at specified heights, and the treatment aims to create a fuel reduced zone immediately adjacent to the urban edge and other assets.

Slashing and mowing programs for fuel management generally commences as grass curing, or drying,  reaches a specified range, and may be repeated several times during a fire season, depending on grass growth reaching predetermined thresholds.

Fuel Management Implications:

Advantages

• Slashing compacts the grass fuel and lessens the intensity of bushfires, making suppression efforts more effective
• Slashing produces mulch that can maintain higher moisture levels, thus reducing flammability
• Slashing maintains a uniform fuel height and precludes the establishment of a woody understorey (less fuel). In the case of grassy woodland slashing, slashing breaks the fuel 'ladder' from ground to green canopy making crown fire less likely, also improving visibility and therefore access and crew safety
• Slashing of exotic (summer-brown) grasses, if carried out early enough, and subject to soil moisture levels, prolongs the growing phase and can act as a fuel break or buffer; and
• Roadside mowing of pullover verges provides vertical separation between vehicles and potential ignition sources (eg bearing / break failure), thus reducing risk of ignition.

Disadvantages

• Grasslands are quick to recover and fuel loads can increase quickly following mowing. An area may require more than one mowing during the course of the season;
• Mowing or slashing is only possible within areas relatively clear of rocks, trees and shrubby understorey.