John Elliott wrote:Sounds like great biochar. The reason cedar is not recommended in hugelkultur is that it is slow to break down. Fungi can handle the lignin and cellulose, but the oils in the cedar (which give it its particular aroma) are the problem. It is slow-going until those oils either (a) leach out or (b) get solarized in the hot sun or (c) eaten by some beetle that can tolerate the oils. But now you have gone and burned it, and in the process of charring it, have probably driven off a lot of those oils. So it may rot quite a bit faster than an unburned piece of cedar. I say go ahead and throw them in the hugel.
That's very encouraging because I have a ton of these and hate to see them waste. I also read that cedar is allelepathic. First, is that true and if so do you think charring it helped rid it of that property?
Brandon Greer wrote:I know that cedars are bad for hugulkultur but I'm curious to know if charred cedar would be any better.
Where I live we have western red cedar. This species is extremely rot resistant in most circumstances (buried in peat it can last for thousands of years, buried in regular soil the center of a very large diameter tree can last for hundreds.), and although it burns readily (being full of air (light wood) and volatile oils), when dry, it has something in it that prevents it's live trees from burning completely (thus the tree's can stand dead 100 years after a fire that has reduced every other tree to ashes or rot food for new growth; and sometimes the cedars are not completely killed when everything else is gone and just a strip of bark feeds a branch or two way up near the crown). Burnt Cedar can fall on the ground and be preserved for even longer than a regular cedar that has fallen.
I don't have any experience with Eastern Cedar, but as far as the western cedar goes I doubt if burning/charring cedar would be any better for hugulkultur, in the regard of breaking down and holding nutrients. That said, despite claims that cedar might not be great for hugulkultur, I see plenty of things growing on and in dead western red cedar (charred or otherwise) stumps, including several species of native berries, and ferns, as well as whole nurseries of young western hemlock trees on fallen logs. If I was to use cedar in a hugul bed, I would probably plant something that would naturally like it. The bonus of using cedar would be that the bed might be more stable as it might not break down as fast. If it was mixed with other woods, it would probably add to the diversity of your fungi/micro-fauna/flora because it would take a different group of beings to break down those persistent resins. Some things do not like cedar, and so some people do not make garden beds out of it or use cedar stakes in the garden. I have not noticed any effect. The allelopathic properties may have to do with a living tree. You might want to search out the allelopathic properties of cedar. Other than that, I would say use it, but I would probably put other easier to digest foods/sponges in the upper layers of your hugul bed.
Your burnt wood could become a bit like biochar if you inoculate it with some nutrients (compost, urine, manure).