Best Firewood Species in Australia: Red Gum, Ironbark, Box Gum and the Rest, Compared

Short version: as a broad rule, the denser and heavier a dry piece of hardwood feels for its size, the longer and hotter it tends to burn, and the better the coals it leaves behind for keeping a fire going overnight. Ironbark and river red gum sit at the dense, long-burning end of what is widely and commonly sold across Australia; box and sugar gum sit in a solid middle ground; mallee root is famous for burning hot and long despite being an unusual, gnarly-looking product; and softwoods like pine burn hot and fast but do not hold a fire the way the hardwoods do. None of the figures below are precise lab numbers, they are general, widely understood comparative knowledge among firewood sellers and burners, so treat them as a guide to relative performance, not an engineering spec.

Why density is the number that matters

Wood energy content per kilogram does not vary as wildly between species as people assume, most dry wood is a similar story chemically. What varies enormously is density, how much wood mass fits into a given piece of a given size. A dense species like ironbark packs a lot more burnable material into a round of a given diameter than a light species does, which is why it burns longer and produces more heat per load, and per barrow-load carried inside. That density difference is also why dense hardwoods are heavier to split, heavier to carry, and generally slower to season all the way through, since moisture has further to travel out of a denser piece.

Red gum (river red gum)

Probably the most widely sold and recognised firewood species on the east coast and through South Australia and Victoria. Dense, burns hot, holds a fire well, and leaves a solid coal bed, which makes it a strong pick for overnight burning in a wood heater. It has a reputation as close to an all-rounder benchmark that other species get compared against in casual conversation among buyers. Downsides are mostly practical: being dense, it takes longer to season fully than lighter species, and green red gum sold as seasoned is a common enough complaint that it is worth testing (see our seasoned vs green guide) before you commit to a load.

Ironbark

One of the densest and hottest-burning firewoods commonly available in Australia, and often described anecdotally as burning hotter and longer than red gum for an equivalent volume, though exact comparisons vary with moisture content and how it was seasoned. Excellent coaling qualities, which suits it well to slow combustion heaters run overnight. The trade-off is that its density makes it genuinely hard work to split by hand, and like red gum it needs a proper seasoning period to dry out fully, a green ironbark round can stay stubbornly damp in the centre for a long time.

Box and sugar gum

A step down in density from red gum and ironbark but still a solid, reliable hardwood firewood, commonly sold and burned across South Australia and parts of Victoria in particular. Easier to split than ironbark, seasons a bit faster because it is less dense, and still gives a decent, useful burn with reasonable coaling. A sensible middle-ground buy if ironbark or red gum is priced at a premium locally, or if splitting by hand is a real consideration.

Mallee root

An unusual product: not a straight log at all, but the dense, twisted root mass of mallee eucalypt species, often sold in irregular chunks. Mallee root has a strong reputation among firewood users for burning extremely hot and for an unusually long time for its size, owing to its very high density, it is some of the densest firewood commonly available. Because of its irregular shape it can be awkward to load into some fireboxes, and it is not always as widely available as straight-log species, but where it is sold it is generally regarded as premium, long-burning firewood.

Softwoods (pine and similar)

Pine and other softwoods burn hot and fast, light easily, and are genuinely useful as kindling or for a quick, short fire, a barbecue or a camp fire that does not need to last all night. What they do not do well is hold a long, steady burn or leave a useful coal bed, because low density means the wood is consumed quickly. Softwoods also tend to carry more resin, which can contribute to faster creosote build-up in a flue if burned regularly as a primary fuel rather than as kindling or a supplement. As a household's only wood heater fuel through winter, softwood alone is a poor substitute for a proper hardwood, but as a fire starter or mixed in for a quick evening fire, it has a real place.

Mixed hardwood loads

A lot of what is sold commercially, and listed under "mixed hardwood" in classifieds, is exactly that: a blend of local hardwood species rather than a single named type. This is not necessarily a downside, mixed loads are often simply whatever the seller has processed recently from local sources, and a well-seasoned mixed hardwood load will generally still outperform any softwood-only load. If species matters to you for a specific reason, ask the seller directly what is in the mix rather than assuming.

Putting it together when you buy

Species is only one part of what you are actually paying for. A perfectly seasoned box gum will outperform a green, unseasoned ironbark every time, moisture content matters more than species once you are comparing a well-seasoned load against a poorly seasoned one. Check both: use the moisture and knock tests regardless of species, confirm you are getting a genuine cubic metre rather than a vague "load", and if the wood has travelled any distance, particularly across a state line, check the biosecurity considerations before it arrives.

Ready to buy, browse firewood listings and filter by species where sellers have specified it. Selling a specific species and confident in its quality, list it free and name the species in the title, buyers searching for ironbark or red gum specifically are easy to convert when the listing tells them exactly what they are getting.