Designing your garden for fire resilience

Fire has played a part in the Australian landscape for many thousands of years. Consequently, Permaculture design has a focus on designing to exclude wildfire from the home and garden. This involves multiple strategies, which include house design, water supply, firebreak areas surrounding both individual houses and also hamlets of houses, animal yards, and other important human infrastructure.

Windbreaks of fire retardant species can be a useful strategy to attempt to slow a cooler fire front as it approaches a house or settlement. A well-maintained windbreak would consist of species with a low volatile oil content, less flammable leaves or bark, and trees and shrubs which don’t lose a lot of leaves or dead branches over time. They would be placed outside of the fire-protection zone. To retain the fire- retarding qualities these plantings will need to be either kept moist through irrigation, or be part of a water retaining design e.g. planted on swales to have a permanent source of water available, once water has infiltrated over a number of years.

Other important strategies include the maintenance of separation between areas of fuel. Firstly, by pruning lower and dead branches, vertical separation is maintained. Having areas of ploughed land or scraped back firebreaks, can provide horizontal separation in a cool fire. Keeping trees hedged and managed, and the incorporation of compost in to the soil to maintain its water-holding capacity, and mowing, irrigated areas, roads, maintenance of forest trails, and clearing up and composting of dead leaves and branches, are all useful strategies. Wood-chippers are very useful for tree prunings, to be used for compost. These strategies have use in low to severe fire situations. Once a fire storm develops in either extreme or catastrophic conditions, the situation is extremely unpredictable and any plant that becomes dry enough will burn. The following is a list of useful plants which may be less likely to burn in the less extreme fire situations

Low firebreak
Common name	Botanical name	Flammability
Agapanthus*	Agapanthus africanus* and	Low
	A. orientalis *
Clivia	Clivia miniata	Low
Crinum Lily	Crinum pedunculatum	Low
Day lily	Hemerocallis aurantiaca	Low
Warrigal Greens	Tetragonia tetragonioides	Low
Medium firebreak Shrubs
Coprosma	Coprosma repens	Low
Rhododendron	Rhododendron sp.	Mod
Rhododendron Tropical	Rhododendron Vireya	Mod
Tagasaste*	Chamaecytisus palmensis*
Trees
Deciduous fruit trees	Low flammability
Apples	Malus domestica
Carob	Ceratonia siliqua
Cherries	Prunus avium	Low
Feijoa	Acca sellowianna
Fig	Ficus carrica
Mulberries	Morus rubra and M.alba	Mod
Nashi Pear	Pyrus pyrifolia
Pears	Pyrus calleryana
Persimmon	Diospyros kaki	Mod
Plums European	Prunus domestica	Low
Plums Japanese	Prunus salicina	Low
Most nuts except Macadamia
Hazelnut	Corylus avellana	Low
Deciduous European Trees
Oak	Quercus robur
Willow*	Salix babylonica*	Mod
Box-Elder Maple *	Acer negundo
Sycamore*	Acer pseudoplatanus*
Chinese Elm	Ulmus parvifolia
Ash	Fraxinus sp.*

Note: Populus sp. Poplar tree, Platanus sp., Plane tree and Pittosporum undulatum Pittosporum are regarded as hard to burn by the authors of Fireguard 3 (an older publication), whereas Chladil and Sheridan 2006, regard them as having high flammability.

* These plants may become environmental weeds.

Australian rainforest plants

http://anpsa.org.au/fire.html  accessed 04/12/2019  “*ANPSA knows of no plant that is completely non-flammable. ANPSA cannot guarantee that the species listed will not burn…they are simply more resistant than many other species*.”

Deep Yellowwood	Rhodosphaera rhodanthema	ANACARDIACEAE
Red Olive-Berry	Elaeodendron australe	CELASTRACEAE
Orange Boxwood	Denhamia celastroides	CELASTRACEAE
Black Wattle	Callicoma serratifolia	CUNONIACEAE
Crabapple	Schizomeria ovata	CUNONIACEAE
Black Plum	Diospyros australis	EBENACEAE
Silver Croton	Croton insularis	EUPHOPRBIACEAE
Silver Croton	Croton insularis	EUPHORBIACEAE
Red Kamala	Mallotus philippensis	EUPHORBIACEAE
Bolwarra	Eupomatia laurina	EUPOMATIACEAE
Kurrajong	Brachychiton populneus	MALVACEAE
Flame tree	Brachychiton acerifolius	MALVACEAE
White Cedar	Melia azederach	MELIACEAE
Whalebone tree	Streblus brunonianus	MORACEAE
Golden Penda	Xanthostemon chrysanthus	MYRTACEAE
Cheese tree	Glochidion ferdinandi	PHYLLANTHACEAE
Long leaved- quinine bark	Petalostigma triloculare	PICRODENDRACEAE
Native Frangipani	Hymeonosporum flavum	PITTOSPORACEAE
Native Frangipani	Hymenosporum flavum	PITTOSPORACEAE
Muttonwood	Myrsine howittiana	PRIMULACEAE
Firewheel tree	Stenocarpus sinuatus	PROTEACEAE
Tree Lomatia	Lomatia fraseri	PROTEACEAE
Buckinghamia	Buckinghamia celsissima	PROTEACEAE
Native Hydrangea	Cuttsia viburnea	ROUSSEACEAE
Coast Canthium, Supple Jack	Cyclophyllum coprosmoides	RUBIACEAE
Golden Ash	Hodgkinsonia ovatiflora	RUBIACEAE
Flintwood Mountain Cherry	Scolopea braunii	SALICACEAE
Wild Quince	Alectryon subcinereus	SAPINDACEAE
Steelwood	Sarcopteryx stipata	SAPINDACEAE
Boobialla	Myoporum sp.	SCROPHULARIACEAE
White Hazelwood	Symplocos stawellii	SYMPLOCACEAE
Buff Hazelwood	Symplocos thwaitesii	SYMPLOCACEAE

Other Australian plants

Botanical name	Common name	Flammability
Acacia decurrens	Green wattle	mod
Acacia mearnsii	Black wattle	mod
Acacia melanoxylon	Sally wattle/ Blackwood	mod
Araucaria heterophylla	Norfolk Island pine	mod
Myoporum insulare	Boobialla	moderate

New Zealand Species

List compiled by Robina McCurdy of Earthcare Education Aotearoa  flammability rate from Wyse et al. 2016)

Indigenous Maori name (common name)	Botanical name	Flammability rating
Taupata (mirror bush)	Coprosma repens
Karamu*	Coprosma robusta*	low
Kotukutuka (tree fuschia)	Fuschia excorticata	low
Hange hange (NZ privet)	Geniostama ligustrifolium	low
Mahoe/ whiteywood	Melicytus ramiflorus	Low/med
Ngaio P	Myoporum laetum	low/med
Puaou/ (five finger)	Pseudopanax arboreum	low
Red matipo	Myrsine australis	low
Papauma (broadleaf)	Griselinea littoralis	low/med
Akeake (hop bush)	Dodonea viscosa	med
Karaka (NZ laurel)	Corynocarpus laevigatus	low/med

^P poisonous plant

* may become an environmental weed

References:

Chladhil, M. and Sheridan, J. Fire Retardant Plants, fire_retardent_plants_brochure.pdf Revision 3 2006. Tasmanian Fire Research Fund

Department of Bushfire Services, Fireguard Resource 3. Tree Selection for Fire-Prone Areas. Rosehill NSW

Mollison, B. Permaculture Design Course 1990, Byron Bay

Small Tree Farm www.smalltreefarm.com.au about-retarants.pdf Accessed 4/1/2017, Balingup WA

Wyse, S. V., Perry, G. L. W., O’Connell, D. M., Holland, P. S., Wright, M. J., Hosted, C. L., Whitelock, S. L., Geary, I. J., Maurin, K. J. L. & Curran, T. J. (2016). A quantitative assessment of shoot flammability for 60 tree and shrub species supports rankings based on expert opinion. International Journal of Wildland Fire 25: 466-477. 

Article prepared by Janelle Schafer

There is no guarantee that any of the species listed in this article will not burn. Any species will burn once it is dry enough. Please consult your local fire authority for recommendations for fire protection in your area.