Firewood Moisture Content Chart: Seasoning Times by Species

Dry firewood is under 20 per cent moisture. Here is what each species starts at, how long it takes to get there, and how to check without guessing.

By Zakaria October 17, 2026 3 min read Save to Pinterest

Split firewood drying — Photo: analogicus, Pixabay Content License, via Pixabay

On this page

Under 20 per cent, measured on a fresh split face. Everything else on this page is about how long each species takes to get there.

The short answer

Firewood should be under 20 per cent moisture, measured on a freshly split inner face rather than the outside of a split, which reads several points too low. Softwoods such as pine and spruce reach that in six to nine months; medium hardwoods like ash, birch, cherry and maple take about a year; dense hardwoods such as oak and beech need two. Above 25 per cent a large share of the fire's energy goes into boiling water out of the wood, the flue runs cooler, and the smoke condenses as creosote. Split, stacked off the ground, covered on top with the sides open is what dries wood.

Under 20%, on a fresh split face
Softwood 6–9 months, medium hardwood ~1 year, oak and beech 2 years
Oak reads dry outside while the centre is still wet
Wet wood means creosote, cool flues and blackened glass
Top cover, open sides — wind dries wood, not a tarp over everything

The chart

Green moisture content and realistic seasoning time, split and well stacked

Species	Green MC	Time to under 20%	Notes
Pine, spruce, fir	50–70%	6–9 months	Fast. Resinous, more sparks
Poplar, willow	60–100%	6–9 months	Dries fast, burns fast, low heat
Ash	30–45%	9–12 months	Lowest green MC of the common hardwoods
Birch	45–55%	~12 months	Bark sheds water — stack so it can breathe
Cherry	45–55%	~12 months	Pleasant, moderate heat
Maple	50–65%	12–18 months	Sugar maple at the longer end
Hickory	50–60%	12–18 months	Very high heat output
Beech	50–65%	18–24 months	Excellent once dry
Oak	60–80%	24 months	The one people rush. Worth the wait
Elm	60–80%	24 months	Interlocked grain — hard to split

Measure the inside, not the outside

The surface of a split dries within weeks. Pressing a meter to it on a two-month-old oak round can read in the teens while the core is still at 40 per cent.

Split a piece and test the fresh face, pins across the grain, wood at room temperature. Cold wood reads low.

Reading the wood without a meter

Not as good as a meter, but reliable enough to sort a stack:

End checks — cracks radiating from the centre of the end grain
Sound — two seasoned pieces knocked together ring; wet ones thud
Bark — loose or falling off on many species
Weight — obviously lighter than a green piece the same size
Soap test — rub dish soap on one end and blow at the other. Bubbles mean air is moving through, so the wood is dry

What actually dries wood

Split it. Round logs dry through the ends only and take far longer
Off the ground — pallets, rails, anything with air underneath
Single rows where you can, with gaps for air
Cover the top only. A tarp down the sides traps moisture and grows mould
Wind matters more than sun. An open, breezy spot beats a sheltered sunny one
Stack by season so you are burning last year’s, not this year’s

Why it matters beyond lighting easily

Three things get worse as moisture rises:

Heat. Energy goes into evaporating water instead of into the room. At 25 per cent a meaningful share of the fire’s output is doing nothing useful
Creosote. Cool smoke condenses in the flue as a tarry deposit. That deposit is what burns in a chimney fire
Smoke. Heavy visible smoke, which in many areas is now regulated for wood sold or burned

A moisture meter costs very little and settles every argument about a stack. For anyone burning more than a few fires a year it is the single most useful thing to own after the axe.

Common questions

What moisture content should firewood be?

Under 20 per cent, measured on a fresh split face. Below that the wood lights easily, burns hot and produces little smoke. Between 20 and 25 per cent it will burn but noticeably less well, and above 25 per cent a large part of the fire's energy goes into boiling water out of the wood rather than heating the room. Most wood stove and appliance manufacturers specify under 20 per cent, and in several countries it is now the legal threshold for firewood sold in small quantities.

How long does firewood take to season?

Six months to two years, depending mostly on species and how it is stacked. Softwoods such as pine and spruce can be ready in six to nine months. Most medium hardwoods — ash, birch, cherry, maple — take about a year. Dense hardwoods such as oak and beech need a full two years, and oak in particular is notorious for reading dry on the outside while the centre is still wet. Split, stacked off the ground, covered on top only, with the sides open to the wind, is what actually dries wood.

How do I measure firewood moisture?

Split a piece and press the meter pins into the freshly exposed inner face, across the grain, at room temperature. Measuring the outside of a split gives a reading several points too low because the surface dries first, which is how people convince themselves wet oak is ready. If you have no meter, the signs are end cracks radiating from the centre, a hollow knock when two pieces are struck together, loose bark, and a weight that is obviously lighter than a green piece of the same size.

Is ash really burnable green?

It is the species that generates this claim, and the claim overstates it. Ash has a lower green moisture content than most hardwoods — often in the 30s rather than the 60s — so it burns sooner than oak and will light when relatively fresh. It still burns far better seasoned, and the old rhyme about ash burning green is about relative behaviour, not an argument for skipping seasoning.

What happens if you burn wet firewood?

You get less heat and more deposits. Energy is spent evaporating water instead of warming the room, the fire runs cooler, and the cooler smoke condenses in the flue as creosote — the tarry layer that causes chimney fires. Wet wood also smokes heavily, which matters where there are smoke control rules, and it blackens stove glass within minutes.

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The sawn ends of pine logs stacked in a pile, growth rings showing

Gear & Reviews · Oct 11, 2026