Creating Defensible Space Around Your Home

Defensible space is the buffer zone you create between your home and the grass, trees, shrubs, and other vegetation that surround it. It is the single most effective action a homeowner can take to improve the chances of their home surviving a wildfire — and to give firefighters a safe place to work if they defend your property.

When a wildfire approaches, it does not simply arrive as a wall of flame. Embers travel kilometres ahead of the fire front, landing on roofs, in gutters, against fences, and in dry vegetation beside your house. The majority of homes that burn during wildfires are ignited by these airborne embers, not by the main flame front. Defensible space directly reduces this ember risk by eliminating the fuels closest to your structure.

⚠️ In many jurisdictions, maintaining defensible space is a legal requirement. Failure to comply can result in fines and may affect your insurance coverage. Check your local fire authority regulations before any major changes.

Understanding the Two Zones

Defensible space is typically divided into two distinct zones, each with specific vegetation management requirements.

Zone	Distance from Home	Goal
Zone 1 (Lean, Clean, Green)	0–9 metres (0–30 ft)	Eliminate or drastically reduce combustible plants and materials
Zone 2 (Reduced Fuel Zone)	9–30 metres (30–100 ft)	Reduce fuel density so fire cannot crown and travel to Zone 1
Extended Zone (slopes)	Up to 30–60 m additional	Compensate for slope-accelerated fire spread
Ember-ignition zone	Under eaves, in gutters, vents	Prevent ember catch in structural gaps

On sloped land, zones must be extended further downhill. A 10% slope increases effective fire travel speed significantly — add 10 extra metres of Zone 2 for every 10% of slope gradient.

Zone 1: The Lean, Clean, Green Zone (0–9 metres)

This is the most critical zone. Vegetation here must be carefully managed year-round.

Plants and vegetation:

• Remove all dead plants, grass, and weeds
• Mow grass to a maximum height of 10 cm (4 inches)
• Choose fire-resistant plants with high moisture content (succulents, deciduous species)
• Space plants so fire cannot travel continuously from one to the next
• Remove all branches within 3 metres of the ground on any tree
• Keep any tree canopy at least 3 metres away from your roof and chimney

Structures and materials:

• Clear gutters of dry leaves and pine needles after every wind event and before fire season
• Remove combustible furniture, doormats, and decorations from decks during high-risk periods
• Store firewood at least 9 metres from your home
• Replace wood fencing touching the house with metal or masonry sections
• Ensure garden hoses can reach all corners of Zone 1

Common Zone 1 mistakes to avoid:

• Planting conifers or eucalyptus close to the house (highly flammable even when green)
• Allowing ivy or ground-cover vines to contact the exterior wall
• Leaving a wooden deck with combustible materials stored beneath it
• Placing mulch directly against the foundation wall (use gravel instead)

Zone 2: The Reduced Fuel Zone (9–30 metres)

Zone 2 is about breaking the continuity of fuel so that a surface fire cannot climb into tree canopies and become a crown fire, which travels far faster and generates more radiant heat.

Tree spacing:

• Space trees so crowns do not touch — minimum 3–5 metre gaps between canopy edges
• On steep slopes, increase spacing: trees further downhill require greater separation
• Remove all dead trees and standing dead wood (snags) unless they provide wildlife habitat at a safe distance
• Limb up all trees to remove branches within 3 metres of the ground

Shrubs and understorey:

• Group shrubs in islands with bare soil or low-lying plants between groups
• Remove shrubs growing directly beneath tree canopies
• Mow or cut back annual grasses before they dry out in summer

Slope Gradient	Zone 2 Minimum Radius
Flat (0–10%)	30 metres
Moderate (10–20%)	40 metres
Steep (20–30%)	50 metres
Very steep (>30%)	60+ metres

Hardening Your Home Against Embers

Defensible space vegetation work must be paired with home hardening to be truly effective. Embers can enter a structure through surprisingly small openings.

Vents and openings

• Cover all attic and foundation vents with 1.5 mm (1/16 inch) or finer metal mesh
• Install spark arrestors on chimneys
• Seal any gaps in soffits, eaves, and around pipes with metal mesh or caulk
• Keep garage doors closed during wildfire events

Roof and gutters

• Choose non-combustible roofing: metal, tile, or Class A asphalt shingle
• Install gutter guards to prevent leaf accumulation
• Consider ember-resistant gutter covers made from metal mesh

Walls and windows

• Double-pane or tempered glass windows are more resistant to radiant heat
• Cover vents behind shutters during evacuations
• Remove combustible awnings and replace with metal or fire-resistant alternatives

Decks

• Fill gaps in deck boards where embers can accumulate underneath
• Use non-combustible skirting around the deck perimeter
• Store all combustible cushions and furniture indoors during red flag conditions

Seasonal Maintenance Schedule

Defensible space is not a one-time project — it requires ongoing maintenance tied to the seasonal fire cycle.

Spring (before fire season):

1. Inspect the entire Zone 1 boundary after winter rains
2. Remove any new seedlings or volunteer plants within 3 metres of the house
3. Apply 5 cm of gravel mulch around the foundation to replace any organic mulch
4. Test all garden hoses and outdoor taps for full functionality
5. Clear gutters of winter debris — leaves, pine needles, and seed pods

Early summer:

1. Mow grass in both zones before it dries out
2. Cut back any shrubs that have grown into prohibited spacing
3. Remove lower limbs of trees if new growth has lowered canopy height
4. Inspect roof surface for any accumulated plant debris
5. Clean wood-burning fireplace and check chimney cap is intact

During fire season:

1. Check Zone 1 after every wind event for accumulated debris
2. Remove combustible items from deck and patio during red flag warnings
3. Know your evacuation trigger — do not wait for official orders if fire is near
4. Keep vehicles facing out with keys accessible, fuel tank above half

Autumn:

1. Conduct a full Zone 1 and Zone 2 inspection
2. Document improvements with photographs for insurance records
3. Clear gutters again before the first winter rains
4. Dispose of green waste promptly — do not allow piles to dry near the house

Selecting Fire-Resistant Plants

Not all plants are equally flammable. Fire-resistant plants tend to be high in moisture content, low in resin or volatile oils, and non-accumulating of dead material. They do not eliminate fire risk but significantly reduce it.

Preferred characteristics:

• Leaves with high moisture content that do not dry and curl in heat
• No accumulation of dead material within the plant structure
• Low sap or resin content
• Open branching structure rather than dense foliage masses

Plants to avoid in Zone 1:

• Conifers (pines, firs, spruces) — resinous and highly flammable
• Ornamental grasses — dry out and carry fire rapidly
• Rosemary and lavender — aromatic oils are highly volatile
• Bamboo — hollow stems act as a chimney when burning
• Any plant with shreddy or papery bark

⚠️ Even fire-resistant plants will burn under extreme fire conditions. The goal is to slow fire spread and reduce the heat reaching your home — not to create a fireproof landscape.

Working With Neighbours and the Community

Defensible space that ends at your property line provides less protection than a community-wide approach. Embers travel freely across property boundaries, and a neighbour's neglected vegetation becomes your hazard.

1. Share defensible space information with adjacent neighbours before fire season
2. Offer to help elderly or mobility-limited neighbours clear their zones
3. Contact your local fire authority about free vegetation inspection programmes
4. Participate in community FireSafe councils or equivalent local bodies
5. Advocate for local government weed abatement programmes on roadsides bordering your community

Quick Reference

Task	Zone 1 Requirement	Zone 2 Requirement	Frequency
Grass mowing	≤10 cm height	Cut before dry season	Monthly in season
Tree limbing	No branches <3 m high	No branches <3 m high	Annual
Tree crown spacing	Canopy 3 m from roof	Crowns 3–5 m apart	Annual check
Gutter clearing	Remove all debris	N/A	After each wind event
Dead plant removal	All dead material removed	Remove dead trees	Annual
Firewood storage	9 m minimum from home	Stacked neatly	Ongoing
Vent screens	1.5 mm metal mesh	N/A	Inspect annually
Mulch type	Gravel only at foundation	Organic mulch acceptable	Replace as needed