humidity in wood for biochar

Hi! For my pdc next september, the group will come at my home for a workshop on biochar. I don't have many wood ready to burn. How does fresh wood can be ? I though to cut down new resinous tree for a BB, so the branch that i could use for the biochar would be only a month old. Would it be ok for the workshop you think ?

It's possible with green wood, but it would take a long time. All the water has to evaporate before pyrolysis begins.

I make most of mine with fresh green branches, But, I don't get anywhere near as serious as some people in regards to the quality. It works great for me considering that my main objective is wildfire fuel reduction anyways.

True. I think it's a matter of scale.

When I'm doing a larger burn (trench) and I have a big bed of hot coals, adding a percentage of green branches doesn't matter. There's more than enough waste heat to cook off the moisture. It might even help slow down the burn a bit and reduce ash.

Are you using a TLUD, pit, or just quenching an open fire?

I wouldn’t recommend green wood for a TLUD, but you can get away with green wood in a pit or open fire.  Find something nice and dry like pallet wood to get it started then you can put all the green wood you want on, just smokes a bit more.  Keep it under 3-5cm for best results.  Instead of cutting the tree down, look for something that needs pruning.  I get a lot of material that way while opening up light for groundcover and not killing the trees.

I toss green branches on the kontiki when it's good and hot. They burn just fine and if I keep the rate down it doesn't really add much smoke. More sap bubbles out of the cut ends and that's about the only way I can tell the difference between green sticks and dry ones a few minutes into burning.

Green logs and root balls, OTOH, barely carbonise at all. Every now and then I'll put a few of these in the middle of a burn, knowing full well that I'll pull them out after the fact and put them in subsequent batches. Sometimes it takes 4-5 burns to completely char a dense stump section. It often ends up as a coin toss: biochar or hugel the gnarly pieces.

It is most helpfull, thanks all for the opinion. I'll try a mix of green and dry woods then. It will be in a pit of 2m large by 1meter deep that i have yet to shovel. And i intend to use branch of a spruce that is already tilting, he will not survive many more winter, so i'll use it before it break or rot, and some old dry slab of wood.

Sounds good. That is the same size trench as what I use.

I think that if you're not in a hurry, setting green wood aside for awhile will give you a better burn that results in more carbon, a more efficient fire, and less smoke.  That's what I do.  I know when I started the piles, so I know which pile is seasoned wood, and which is still green.  Then I make sure it's dry.  I use a TLUD, though.

John S
PDX OR