Fire is a process, not a disaster
Savannas burn. So do Mediterranean shrublands, boreal forests, and most temperate grasslands. These systems evolved with fire over millions of years. Their species need it to germinate, regenerate, and hold structure.
Remove fire and the system unravels. Fire-dependent species decline. Fuel piles up. The open, light-filled understory closes in.
African and Australian savannas show this most clearly. A low-intensity burn every one to five years keeps the grass layer rich and the tree canopy spaced. Skip those burns and woody shrubs march in, shading out the grasses and converting savanna to thicket. Bush encroachment cuts grazing capacity, lowers diversity, and stores up fuel for the catastrophic crown fire that follows.
Mediterranean systems carry this further. The garrigue of southern France, California chaparral, and South African fynbos hold tens of thousands of endemic plants. Many have serotinous cones that crack open only after fire. Others resprout from lignotubers within weeks of burning. Exclude fire here and you lose species permanently.
How suppression made fires worse
The twentieth-century policy of total fire suppression across North America, Europe, and Australia was well-meant and ecologically disastrous. By stopping the small, frequent ground fires that shaped these landscapes for millennia, suppression let fuel stack to unprecedented levels.
When fire finally arrived, it was not gentle. It was a crown fire that killed mature trees, sterilised soil, and erased the ecosystem it was supposed to protect.
The numbers. Western US forests that burned every 5 to 15 years went 50 to 100 years without fire. The 2020 fire season in California, Oregon, and Washington burned over four million hectares. Australia's 2019-2020 Black Summer fires burned ten million hectares and killed an estimated three billion animals.
Suppression also rewires species composition. In grasslands, woody plants invade. In forests, shade-tolerant understory species build a fuel ladder that carries flame from the ground into the canopy. The irony stings. Suppressing fire to protect forests creates the fires that destroy forests. Reforestation after a high-severity burn is slow, expensive, and uncertain.
Controlled burning: how to do it
A prescribed burn is a planned fire run by trained crews under specified weather and fuel conditions. Objectives are written down. Control lines are cut. Suppression equipment waits on the line. The fire achieves something specific: fuel reduction, germination of fire-cued seed, knockback of invasive woody species, or maintenance of open structure.
Timing. Timing decides what the burn does.
A late-winter burn in temperate grassland strips dead thatch, warms the soil, and gives native warm-season grasses a head start over cool-season invasives. A late-summer burn in savanna kills woody seedlings during active growth while mature trees with thick bark shrug it off. Match timing to vegetation type, and lean on indigenous fire knowledge where it survives. It usually encodes centuries of careful observation.
Mosaic burning. Burn part of the site, not all of it.
A patchwork of recently burned and unburned ground supports more biodiversity than a uniform burn. Invertebrates, small mammals, and ground-nesting birds shelter in unburned patches and recolonise the burned ground as it recovers. Aim for no more than a third of a site per year, rotated on a three- to five-year cycle.
When you can't burn
Sometimes you can't. Buildings sit too close. Air quality rules forbid smoke. Trained crews aren't available. The neighbours say no.
Mechanical work covers part of the gap. Mowing, brush cutting, and grazing pull biomass down. They don't replicate the nutrient flush or the seed-cracking heat of fire, but they hold structure on urban-edge sites and small reserves.
Chainsaw work opens up shrub-invaded grasslands and savannas. Chip the cut material and spread it as mulch, stack it into dead wood habitat piles, or haul it off if fuel reduction is the goal. Cattle, goats, and sheep at managed stocking rates can hold back woody regrowth. Watch the rates. Overgrazing produces its own ruin.
Thin then burn. Combine the two where you can.
Mechanical thinning of dense understory drops fuel loads to a level where a controlled burn becomes safe. The burn then maintains the open condition the thinning created, at a fraction of the cost of repeating mechanical work every few years. This is now standard practice across fire-adapted forests of the western US and southern Australia, and it sits at the centre of pragmatic ecosystem restoration.