question about ash wood for burning in a stove

[steve rollnick]

Friends,

Ash has this reputation for being great wood for fires and stoves. It sure feels nice and dense. Seems to burn hot and slow, even unseasoned, just as they say in that famous poem about ash wood.

But I have a question:

When I put a moisture meter on a piece of newly cut unseasoned ash, it registered at 37%, just as high as newly cut oak? So how come you can use it unseasoned, and how come it burns so well so full of moisture?

Steve

[RichardKing]

Its all to do with the density & texture of the wood.

I dont have figures to hand, but I suspect that "green" Oak heartwood is probably about twice as dense as Ash. Mind you, I believe all woods will burn green if they are on a good bed of embers.

Its all very well burning green wood, but a large proportion of your heat is wasted turning water into steam which goes up your chimney. Dont forget that water has the greatest latent heat of any known substance, in other words, it takes more energy to raise its temperature than anything else for a given weight. About ten times that of Copper .

Thats why condensing boilers were invented to recover the wasted heat in steam.

[steve rollnick]

Thanks Richard. I still dont get it!

Whatever the density of the wood, and yes, oak heartwood seems much more dense than ash, my question was about moisture content. We agree that green, high moisture content wood is not ideal for burning. You've explained why.

So how come ash is often described, in poems and wise wood-burning advice, as fine for burning even when newly cut, when my moisture reading produced amounts of 35-37%?

What's so special about burning ash green?

Still sounds like an old wives' tale, unless someone can enlighten me?

Steve

[mikepepler]

Actually, it's not he Ash that's giving the odd reading, it's the oak. 37% is low for freshly felled wood, and expected for Ash, but oak should be higher. Check the top range for your meter - mine only reads up to 40%, anything above that still reads 40.

For burning, your wood should definitely be below 30%, and ideally closer to 20%. To get to 20% will take two years, and it's best to split the wood so it can dry easily.

[steve rollnick]

Mike,

Thanks. I dont mean to wind you up, but you havnt answered the question! (smile)

Yes of course, the oak freshly cut might be super moist, off the meter scale. And I dont see the ash reading as odd in any way. 35-38% seems common across many species.

What could be odd and possibly an old wives tale is the idea that ash can be used even when newly cut and unseasoned. here's the poem (check the last lines of each verse):

The Firewood Poem

Beechwood fires are bright and clear

If the logs are kept a year,

Chestnut's only good they say,

If for logs 'tis laid away.

Make a fire of Elder tree,

Death within your house will be;

But ash new or ash old,

Is fit for a queen with crown of gold

Birch and fir logs burn too fast

Blaze up bright and do not last,

it is by the Irish said

Hawthorn bakes the sweetest bread.

Elm wood burns like churchyard mould,

E'en the very flames are cold

But ash green or ash brown

Is fit for a queen with golden crown

Poplar gives a bitter smoke,

Fills your eyes and makes you choke,

Apple wood will scent your room

Pear wood smells like flowers in bloom

Oaken logs, if dry and old

keep away the winter's cold

But ash wet or ash dry

a king shall warm his slippers by.

[mikepepler]

Hi Steve,

Your reading for Ash is fine, but many other species are 50-60% after felling, but as I said, your moisture meter may not go up to these levels. I've just looked up a few websites, and they suggest even 60-80% for freshly felled oak.

If you're moisture meter is accurately reading oak at 30-40% moisture level, then there's probably something up with the tree...

It's all relative. Green Ash (at 35-40%) will burn better than other green wood (at, say, 50-60%). But just because it *will* burn doesn't mean you should use it. Drying it will still allow you to get more heat out when you burn it.

Also, there's the chimney tarring to think about, and ultimately chimney fire risk. I wouldn't burn anything over 30%, and as I said, the closer to 20% the better.

So I think the answers you're after are:

"So how come you can use it unseasoned" - you shouldn't

"how come it burns so well so full of moisture" - it isn't full of moisture compared to other wood, but it's still too much to burn *efficiently*

Cheers, Mike

[RichardKing]

I did answer your question.

ASH HAS A LOWER DENSITY.

The more open structure will allow it to burn more easily.

Your question simply referred to Oak having a similar moisture content.

[woodbodger]

Tentatively dipping my toe in the water here: I don't think all woods are the same as each other at all: I know that one of the best fire woods of all is actually the heart wood of Yew and one of the worst by my own experience is Mahogany ( I once laboriously chopped up an old boat into kindling and I believe it is still smouldering now, could be why they use it to make fire doors) I guess that there are a lot of factors that come in to play apart from moisture such as density, minerals, essential oils, the rate at which sap will wick out of the timber and yes I know this hasn't answered the question either.

[steve rollnick]

Thank you both Richard and Mike.

So the poem is a little over-stretched with the idea that ash can be used "new" "green" and "wet". It might have lower density as Richard kindly educates me about, but as with any other wood, getting the moisture down to 20-25% is still a guideline that applies.......

Understanding wood is such a rich world of knowledge......

Last year we completely ran out and I had to call suppliers. One guy said to me: "What sort of weight do you want?" I said I'd like some well seasoned wood. "Yes, but what sort of weight do you want? One ton, two tons, or what?" You can probably complete the story. I knew less then than I do now. He arrived. Nice heavy weight because it was all green. Some cowboys in this field. That's when I bought a moisture meter.

Thanks guys

Steve

[carlight]

am pretty much with mr bodger on this .

surprised no one has mentioned the potential difference between quick and slow grown ash .

as for moisture meters for firewood , am a tad sceptical .