Is this the wettest (firewood selling )autumn you have known !

[Mr. Ed]

4 hours ago, Paul in the woods said:

The Forestry Commission list green ash as 32% moisture wet basis, the stuff I've cut comes up around 35%.

 

https://www.forestresearch.gov.uk/fr_bec_wood_as_fuel_technical_supplement_2010/

Thanks again Paul. I’m surprised they don’t specify what season the wood was felled - there must be a big difference even in hardwoods. 

[Stere]

Im not sure if live wood moisture  content changes that much annually can't find a good reference about it online apart from this:

 

https://www.nrs.fs.usda.gov/pubs/nh/notes/nh_5_03.pdf

 

Would be interesting to find more recent research info on it for different species.

 

EDIT

 

https://crojfe.com/site/assets/files/4020/routa.pdf

 

Bit drier in summer^

 

Edited January 19, 2024 by Stere

[openspaceman]

3 hours ago, Stere said:

not sure if live wood moisture  content changes that much annually

I have no empirical proof and it's not something easily checked with a moisture meter as mine maxes out above 30% and it doesn't exactly match with figures from oven drying but we do know that in winter sap has to become more concentrated (hence less water) to resist freezing and rupturing living cells.

 

I do have a memory of a piece of pine heartwood having a surprisingly low moisture content when cut in winter.

 

As to ash the only figure I can find that I measured green was 34%mc wwb, oak and birch cut at the same time were 44%.

 

One thing I have been seeing this year which intrigues me is the long dead, large, standing oak I am burning now. It had lost all bark and sapwood, the heartwood is riddled with worm holes, is producing less than half the amount of ash I get from freshly felled hardwoods I otherwise burn.

 

This makes me think that mineral salts  in the sap which normally end up as ash have leached out. Also the flames are very short and red/blue which is what I expect if the volatile solids have gone. Oak never has a lively flame like freshly felled then dried birch.

Edited January 19, 2024 by openspaceman
birch not ash at 44%

[Steven P]

I find the same that trees felled in the winter are drier, though the moisture meter died a while ago so no figures to show it. I always assumed that when asleep they aren't sending water up to the leaves so the trunk hasn't got that water in it.

[GarethM]

Does the cell structure actually freeze in living trees, as I would assume the tree could reduce the water content and change the freezing point ?.

 

Maybe the freezing pops the cells on felled trees and helps to dry it quicker.

Edited January 19, 2024 by GarethM

[Dazza95]

I’ve had some Scots pine sulking when first lighting the fire recently, this stuff was split pretty small and has been in my log store for over 24 months. It gets going eventually but certainly not as easily as I’m used to. I have some oak, laurel and field maple that was processed at a similar time and this seems OK. Perhaps the pine has re-absorbed moisture more readily?