Yes, but don't think of it as burning as much as case hardening and in some methods slight charring. Just about any wood can be treated this way, but you aren't necessarily done after charring, you still may need a coat of oil, depending on species.
Do you have any experience with burning other types of wood?
I would say yes, but this species, unlike Cedar, may require an application of the "land ark." You can just spray it on with a bug sprayer or better yet, a rented commercial sprayer. The oil will go on finer and more conservatively. However, if you didn't oil it, the Douglas Fir would still probably last longer than it normally would without charring. With this species I would wire brush of the excess char.
I'm building a pole barn with doug fir board and batten (wind fall, rough milled, fairly green wood, if it matters) siding this summer and wondered if it would work with that wood as well?
It may if diluted properly.
Would Oxalic Acid work?
Jay C. White Cloud wrote:]I would say yes, but this species, unlike Cedar, may require an application of the "land ark."
So my first question is if it is better to char the posts when they are green, or dry?
Second, how exactly do i gauge the charring process and know when it is optimal?
Third, is there any benefit in charring the entire length of the post?
Naturally they fail first at ground level and with the tops still rather "fresh" as this is a sunny and windy environment even if the soils themselves are often wet, so i know natural wood will hold long enough well above ground level but does it also possibly help wick water out of the post, whereas the char forms a barrier that should be restricted to the in and near ground portion?
Nick Kitchener wrote:Hmmm, I see they also sand the char back to the (fire hardened) wood.
I wonder if its the wood/charr boundary that provides the protection. Everything's about edges right?
Jay C. White Cloud wrote:Hi Nick,
I have seen this study, and several like it. I have a science background and because of that I have learned not to take research at face value. Even if the research is from a college, I want to understand the funding stream that supported the research. Are the researchers themselves affiliated with any large industry in anyway...often they are, and that creates a bias.
Lets just take this study that you reference as an example. 25 post are there sample study? To be blunt, that is ridiculous, you can't determine any kind of viable statistical factors with such a small sample. When I was studying turtles, if I had brought a sample of 25 specimens to my Field Zoology professor, he would have laughed at me and thought I was joking. Also note what species that was chosen for charring. Douglas Fir, well let see, what species could I pick that could be worse... Hmm, Aspen maybe, or maybe a Sugar maple. Why didn't they pick Cedar, or Locust for the charring sample? Again, I smell an agenda, conscious or unconscious, there is bias in this study.
Last, I would point out that, there was no reference to them being taught how, why or by what method they should char the wood. They took one of the worse species they could, burnt it, and stuck it in the ground. I'm sorry that isn't research, that is agenda setting bias, in my opinion and I know many in the science that are guilty of it. Were these folks, I don't know, but there research is weak at best.
There is a long linage behind charring wood as a preservative. Each culture had their own, and unless you have been taught a linage and method, and/or studied several I don't think anyone would be qualified to say it does not work, especially a retired professor, a grad student and all from the forestry department? I would listen to someone from the architecture or social anthropology department first, but that research does not seem to exist.
Anyway you can private message me so I can discuss more about charring seeing as you seem to know a lot and I am new to this concept.
Jay (also my name LOL)
I have several of these lineages taught to me, should you have question, I will do the best I can. Start your research with the Japanese method: shou-sugi-ban. Then come back and ask questions.