The Grange Small Blue Arrow Managing Small Blue Arrow Fire

Fire Management

Heath Plants Adaptation to Fire

Fire has been, and remains, an important factor in maintaining the diversity of heathlands. Plants occurring in heathlands have adapted to regenerate after fire (Specht, 1981). The maximum diversity of species in heathlands occurs soon after fire, although the diversity decreases over the following years. After fire, many of the heathland species rapidly regenerate from underground organs such as rhizomes or lignotubers, while seedlings can begin to germinate a few weeks later.

For certain plants such as Banksia and Leptospermum, fire or high temperatures accelerate the release of seeds that are contained in woody fruits. The chemicals present in the smoke generated by fire are also a key factor in breaking the dormancy of heathland seeds. Chemicals released into the soil during the fire stimulate the germination of seed, with the ash bed effect and sudden exposure of the ground to light providing ideal conditions for germination. Fire also stimulates flowering of rootstock regenerators such as the Red Beaks Orchid (Pyrorchus nigricans) that is found within The Grange.

Many of the species that germinate in the first four years are naturally short-lived.Many others cannot survive fierce competition for space and light immediately after fire, and consequently live only for a short time.

For plants that require fire to stimulate the release of their seeds, fire frequency is important. In heathland, where fires are too frequent, (ie. Less than 7 years apart), or not frequent enough, (ie. over 15 years apart), the character of the heathland is likely to change and species diversity be reduced. If a fire occurs before plants are able to set viable seed, in rare cases, the local extinction of that species may occur.

Area Burned by Control Fire
Area burned by control fire, 2000

Where fire does not occur within an ecologically appropriate period of time, insect and fungal attack may destroy a large proportion of seeds stored in the soil or canopy. Due to the importance of fire in renewing a heathland community, bushland managers at The Grange have determined the way the various plants within the community respond to fire, and thus the appropriate fire frequency. 

This ensures that the requirements of the plant community are met in a sustainable manner. Significant fires are known to have occurred at The Grange in 1984,1991,1999 and 2000 in various parts of the reserve, creating a mosaic of   regeneration. Further controlled burns are planned for the heath communities, as an integral part of the management strategy for the reserve

Fire Management and Residential Areas

The ecology of heathlands and their responses to fire is important when assessing the impact of fire, in an attempt to restore and maintain species diversity in urban reserves such as The Grange.

Because The Grange is in an urban environment; controlled burns are planned and implemented with great care. There are many safety issues that need to be considered prior to a controlled burn and the public should be consulted as part of the process of developing fire management strategies. The City of Kingston's fire management strategy includes:

Due to the high fuel loads that are generally present in heathlands, consideration is given to the reduction of fuel loads (removal of vegetation), placements of firebreaks, and the type and number of fire fighting units. The boundaries of most small reserves, including the boundary of The Grange are mowed to maintain a firebreak.

In theory, medium-intensity fires are needed for regeneration.  In some areas fire may not be an option because of the risk to life and property.  In these instances, alternative management techniques are required to achieve a similar result.