Why is sweet chestnut so hard to dry?

[daltontrees]

Odd you are having problems drying sweet chestnut, I coppice Dec through to March, process , split and net the chestnut March through to May left stacked where sun and wind can get at it, it will be lovely to burn by Oct, might spit a bit though.

Have been doing it this way for over 25 years now and haven't had any complaints from customers to date regarding the logs being difficult to burn.

 

Coppice wood is younger than stem wood and has different characteristics. It is more likely to dry quickly. General theory on this is coming along in a minute....

[daltontrees]

Spiral's comment about tyloses is I think the answer to this.

 

If you think of a bit of wood as a glued-together bundle of narrow straws, each filled with water, it's not far from the truth. These are the water conducting vessels or xylem. When the tree is cut, they are severed and are at least initially able to drain or evaporate their water content. But tyloses prevent this. They are like mini blisters forming naturally from the inside surface of each straw and swelling to block the straw completely, preventing it draining. A bit like blood clots preventing you bleeding indefinitely if you cut yourself. And like blood clots, it is a defence mechanism to stop the tree drying out or letting fungal hyphae making their way up inside the water vessels.

 

Cut a tree and it defends itself in this way. It is a defence that operates as a 'reflex' and doesn't need the rest of the tree to 'tell' it to do it. Like an airbag inside a car, tyloses senses the rapid change and pop out (though not as quickly as an airbag). So cutting a tree into logs will form a wall of tyloses at the cut surface, sealing the water in. On every log.

 

So, wood that has good tylose defences will dry out slowly. Depends therefore on the species.

 

Add to this that tylose formation is probably one of the mechanisms that trees use to convert sapwood to 'dead' heartwood and it might explain BCF's question about why coppice wood dries OK when everyone else is finding cordwood does not.

 

Anybody think there is a correlation between wood that has distinct heartwood and slowness of drying? I can see it the other way round, non-heartwood species like poplar and ash dry out in no time. I'd wager they don't have strong tylose defence.

[Woodworks]

Fantastic

 

Thanks

[se7enthdevil]

excellent explanation sir...

 

 

in log form this seems to be the case but i turned some chestnut bowls leaving the wall 1" thick and they dried withing 6 months. do you think that is because the length of the xylem are mostly very short?

[hedgesparrow]

i have just used over 200 cleft stakes for a river restoration and we and most river jobs use chestnut because it will not rot as quick saw some old stakes in river been there 10 years and still ok.

what they do do in water is turn dark brown. with a reddish outer edge.

plus natural so no toxins in wood to harm the wildlfe unlike most stakes sold which are pressure treated and rot quicker.

[crobinson]

I've burnt a lot of alder as my woods are full of the stuff. I tend to split mine (fairly) wet and dry in log form for 10 months - burns a dream.

[daltontrees]

excellent explanation sir...

 

 

in log form this seems to be the case but i turned some chestnut bowls leaving the wall 1" thick and they dried withing 6 months. do you think that is because the length of the xylem are mostly very short?

 

Yes that will be a major factor. But there is another possibility. And here I confess that I am making it up as I go along but it seems to me that wood that has been dead a while will no longer produce tyloses. Therefore in theory once the initial tylosing (if there is such a word, but I mean the production of vessel blockages by the cell walls) is done and the wood loses this function, maybe the end of a log cna be removed and will take the blocked vessels with it, leaving the remaining wood to dry out quicker.

 

What is needed is an experiment. Cut 5 300mm length of chestnut and 5 at 350mm. Let them dry out a while in identical conditions, then saw 25mm off the ends of the longer ones, then monitor moisture content over a period of a year. If I'm right the re-trimmed ones will dry out quicker.

[se7enthdevil]

interesting idea. probably correct too.

 

my bowls were freshly cut (2-3 days old) as they came from the felling process at windsor royal estate.

[spiral]

Spiral's comment about tyloses is I think the answer to this.

 

If you think of a bit of wood as a glued-together bundle of narrow straws, each filled with water, it's not far from the truth. These are the water conducting vessels or xylem. When the tree is cut, they are severed and are at least initially able to drain or evaporate their water content. But tyloses prevent this. They are like mini blisters forming naturally from the inside surface of each straw and swelling to block the straw completely, preventing it draining. A bit like blood clots preventing you bleeding indefinitely if you cut yourself. And like blood clots, it is a defence mechanism to stop the tree drying out or letting fungal hyphae making their way up inside the water vessels.

 

Cut a tree and it defends itself in this way. It is a defence that operates as a 'reflex' and doesn't need the rest of the tree to 'tell' it to do it. Like an airbag inside a car, tyloses senses the rapid change and pop out (though not as quickly as an airbag). So cutting a tree into logs will form a wall of tyloses at the cut surface, sealing the water in. On every log.

 

So, wood that has good tylose defences will dry out slowly. Depends therefore on the species.

 

Add to this that tylose formation is probably one of the mechanisms that trees use to convert sapwood to 'dead' heartwood and it might explain BCF's question about why coppice wood dries OK when everyone else is finding cordwood does not.

 

Anybody think there is a correlation between wood that has distinct heartwood and slowness of drying? I can see it the other way round, non-heartwood species like poplar and ash dry out in no time. I'd wager they don't have strong tylose defence.

 

Thanks Daltontrees!

 

I am sure it the tylosis that does it, but your explanation was far more eloquent & detailed than mine!

 

spiral

[Goaty]

How about Alder?

 

That was used for 'piles' for jetties and even ones from the Roman period can be found in river mud today.

 

Any-one burned that once dry if it dries at all?

 

Ty

 

 

It seems if you fell it ring it, split it. It cracks open itself more. But I do live on the coast where wind is the norm.

 

Yes it does dry.

 

 

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