The other day I finally took down a white pine that had been dead for a few years. Big base, probably close to 2' in diameter, and a ton of branchy, dead wood up top. I thought it was a great opportunity to convert most of it into biochar for uses in potting mix, future raised beds in the area, and more. I snapped a couple quick pictures of the before and after to share. The yield was around maybe 6 wheelbarrows full of charcoal (I think a 6 cubic foot volume, so pretty substantial). This took about 4 hours of hanging out, enjoying a fire.
Above is the main kiln used. I document this in a video on youtube... ( https://www.youtube.com/watch?v=Eo1xVWR9UPI ) It is made of used sheet metal roofing, cut to about 30" sections, and screwed together into a 10'-ish long flexible strip. The 3 posts are simple tee posts hammered in to keep the form.
It was put together in about 3 minutes, on a flat place near the slash and debris to clean up. Fire started in the bottom and material added as ready to go... I put my other portable kiln you can watch videos on ( https://www.youtube.com/watch?v=lOSDwp20EKM ) next to it and used that too...
This is what it looks like in the morning, after a few hours work cleaning up dead branches and burning them in these kilns, and then quenching them thoroughly with about 40 gallons of water each. Sure, some ash in there, sure, some not fully burnt bits, but a TON of useful charcoal and a great use for otherwise dead, dry branch material.
This flexible, mobile, easy to create, super low cost approach can help you make a massive amount of charcoal. Hopefully this gets some folks excited to try it out!