What Is Defensible Space?
You may have heard the term defensible space in relation to wildfire preparedness, but it’s not just a buzzword — it’s one of the most practical ways to reduce risk around a structure. Defensible space refers to the area surrounding a home, business, or jobsite that’s intentionally modified to slow wildfire spread, reduce available fuel, and improve the odds a structure can withstand ember exposure and nearby flames.
In wildfire conditions, embers are often the biggest threat. They can travel far ahead of the main fire and ignite dry vegetation, wood piles, or other combustible materials close to a building. Defensible space is designed to limit those ignition opportunities.
How to Create Defensible Space Around a Structure
If you’re a homeowner, business operator, or managing a worksite, defensible space is most effective when approached in zones. The closer the zone is to the structure, the more it should focus on reducing ignition risk from embers and direct heat.
Zone 0: Ember-Resistant Area (0–5 feet)
This first zone is your most important buffer. The goal is simple: remove anything that can catch fire if embers land near the building.
Recommended actions:
- Use non-combustible ground cover such as gravel, pavers, or rock
- Avoid mulch or other materials that can ignite easily
- Remove dead grass, leaves, and dry plant material
- Replace wooden fencing directly connected to a structure with non-combustible materials (or create a break)
- Trim back branches that touch or hang close to the structure
Think of Zone 0 as an ember “no-landing zone.” If embers have nowhere to start a fire, the structure is significantly safer.
Zone 1: Lean, Clean, and Green (5–30 feet)
This zone is about reducing fuel and keeping vegetation healthy and maintained. It should be tidy, spaced out, and free of buildup that could carry fire toward a structure.
Recommended actions:
- Remove dead or dry vegetation, including fallen leaves and pine needles
- Keep shrubs trimmed and avoid planting dense clusters near walls
- Maintain spacing so fire can’t easily spread plant-to-plant
- Limit combustible items stored here (patio furniture, planters, wood décor, etc.)
- Prune trees and keep branches separated to reduce “ladder fuels” that allow fire to climb from ground level into the canopy
This zone doesn’t need to be bare — it needs to be managed.
Zone 2: Reduce Fuel Load (30–100 feet)
Zone 2 focuses on lowering overall wildfire intensity around your property by reducing how much fuel is available to burn.
Recommended actions:
- Keep grass cut short and remove dry brush
- Thin and prune trees and shrubs to create more separation
- Clear out deadfall and seasonal debris regularly
- Be mindful of plant placement so vegetation doesn’t create continuous fuel pathways
Fuel management in this zone can reduce how aggressively fire behaves near structures and helps slow fire spread across a property.
Why Defensible Space Matters
Defensible space isn’t about guaranteeing a structure won’t burn — it’s about improving survivability and reducing risk in conditions where wildfire spreads fast and resources may be stretched.
It also supports firefighters by giving them a safer, more workable area if they’re able to defend the structure.
Support for Wildfire Planning and Risk Reduction
Understanding defensible space is one of the most useful first steps a property owner can take. SPIEDR supports communities and organizations with wildfire readiness through wildland fire consulting, equipment rentals, and training — helping clients plan smarter and respond more effectively when wildfire risk rises.
Frequently Asked Questions
How often should defensible space be maintained?
At minimum, it should be reviewed seasonally — especially in spring and early summer — and maintained throughout fire season as vegetation grows and debris accumulates.
Do I need to remove all plants to create defensible space?
No. The goal is not “no landscaping.” It’s reducing ignition risk through spacing, maintenance, and removing dead or highly flammable materials close to structures.
What’s the difference between defensible space and FireSmart?
Defensible space is a core concept within FireSmart-style planning. FireSmart often includes additional guidance on building materials, community planning, and broader risk reduction strategies.
Does defensible space apply to commercial sites and jobsites too?
Yes. Worksites, industrial facilities, and businesses can benefit just as much — especially where equipment, fuel storage, or remote access creates added risk.
