Making wood rot resistant

https://en.wikisource.org/wiki/Popular_Science_Monthly/Volume_5/June_1874/A_New_Process_for_the_Preservation_of_Wood

This is an article from 1874 on preserving wood basically using tannic acid and the simplest form of iron oxide, from what I can tell. I had never seen this method before. So who's tried it?

Interesting article.  I have run into a variety of methods of preserving  wood.   Which is why when someone states that treated wood is bad, I try to determine the method of treatment they are talking about.

Haven't tried it but it sounds pretty cool.  I'm not up on my chemistry...  How would one implement this to test?

https://www.permaculturenews.org/2016/12/05/shou-sugi-ban-preserve-wood-using-fire/

"Nevertheless, if you were to visit Japan and go to Nara prefecture you could find the Horyuji Temple, the pagoda of which was built using Shou Sugi Ban and which is widely considered as the “oldest wooden building in the world” (7, 8) – dating back to 711 AD."

When I planted cedar posts for grape vines, I used something I read out of one of Eric Sloane's books. The topmost end of the post is charred, then planted in the ground. Plant it upside-down. The reason for this is that the tree's natural capillary action draws water from the base, not from the crown. Charring just helps close the pores of the wood more.
I've heard that used motor oil preserves wood cheaply (and how) but I've never tried it.

Interesting. I've heard of that combination being used to stain things black, but wasn't aware it could also be used as a preservative.

Joe Banks wrote:When I planted cedar posts for grape vines, I used something I read out of one of Eric Sloane's books. The topmost end of the post is charred, then planted in the ground. Plant it upside-down. The reason for this is that the tree's natural capillary action draws water from the base, not from the crown. Charring just helps close the pores of the wood more.
I've heard that used motor oil preserves wood cheaply (and how) but I've never tried it.

I have heard about charring cedar posts to create tars that seal the xylem and phloem capillary bundles then setting them in holes filled with gravel as two forms of capillary breaks, but I have not heard about folks planting it upside-down.  Thank you, neat trick Joe!  I was trying to make specific physical sense of it and the first thing that came to mind for me is if the tree had branches in the zone of the post length then the capillaries feeding those branches exist on the down side, but not the upside....cool....less capillaries to worry about breakdown of the seals, those will all stay dry up in the air (though I'd still probably seal that side too just to help plug the other end of the capillaries and further block capillary flow).  But your comment on natural flow in the tree still has me wondering....are there any structures left in dead dried out wood that act like one way valves???  Have you done, or do you know of any tests done to demonstrate that capillary flow differs by direction in dried posts?  This fascinates me!  I didn't find anything with a quick google search.  If anyone knows of any testing please let me know or I will be obligated to carry out experiments :)  If there are differences then I'll want to figure out why if not known (darn enquiring mind...I'm a slave to it).

I would LOVE to see someone do an experiment with 50 fence posts.  

Some black locust, some oak, some cedar, some tamarack, something else?

Several different backfilling techniques - gravel, lime and sand, severely tamped, concrete (just to see how bad it is)

Some charring techniques - just the end, the whole buried part, just the part that's in the "rot zone"

Upside down vs right side up

This new method Jordan found

8 other things.

Set them up in a row in the same conditions.  Attach an arm to the top of each one and put a weight at the end of each arm.  So they each have the same side load applied to them day after day.  2-3x per year apply 50 lbs of side force to the post (first left then right) and measure the amount of movement.

And repeat for a few different soil types (sand, clay, loam).

And if locust posts are in the experiment, you should be young or have descendants so the experiment can continue to ultimate failure

Yeah...love it!  But I would also try with a wood that rots easily and would have untreated controls for all woods to see how much the test methods extended the life of the wood.

Woah there!! Used motor oil will be laced with all kinds of heavy metals and other seriously persistent nasty chemicals and compounds. You really want to set those loose in your soil, and leave them as a legacy for all who come afterwards?

I have never used used motor oil. But I have seen more than one person stand posts up in a 55 gal drum of the stuff.  I would love to see some quality research demonstrate that cleaner inexpensive methods work better

I would love to see a test on the upside-down method of putting in a post.  If I had to make a prediction, I would bet the upside down post will rot faster, simply because you are putting the smaller end in the ground.  When a post rots to the breaking point, it is at the area right at ground level.  I believe it has everything to do with the moisture level right there, and nothing to do with the post sucking water in from above or below.

I think a major reason for putting posts upside down relates to driving them in; the small end going in first will be easier and make the newly driven post more solidly set. There is also more thickness at the top for striking with a maul. If setting in a dug hole and backfilling, I would probably put posts base down for greater strength at ground level.

I agree about sap flow; it flows both up and down in the live trunk.

Mike Haasl wrote:Haven't tried it but it sounds pretty cool.  I'm not up on my chemistry...  How would one implement this to test?

That's my question as well. It looks like the iron oxide is just to make the wood harder, which we can often do without. So it is the impregnation of the tannic acid that most concerns me. He specifically mentions two industrial processes: "Boucherie's process (gravitative force of a heavy column of liquid), and by the modified process of Bréant (successive action, in a close tank, of a vacuum and of a pressure of several atmospheres)." These would be difficult on a small scale for people like us, but what I am thinking is maybe like the common method for better preserving bamboo. Freshly cut bamboo can be placed with the stump end in water, and as the culm lives a few days off of the sap already contained in it, the natural transpiration draws fresh water up the stalk, displacing the sugars and stuff microbes eat. I'm thinking for smaller trees and bamboo, this could be done with mulched or ideally powdered oak bark mixed in the water to as strong a solution as possible. For larger logs, maybe immersion for extended periods or even placing a log with one end in the tannin water may work. I'm sure it may not be as good as pressure treating, but maybe it will help significantly.

Maybe tannin water poured in the hole when setting a post could help. Maybe even some ground oak bark or sawdust added in, on, or around the hole could help. Tannin water could be used periodically through the years to help treat the posts by pouring the water around the post in the ground. Where I live we have clay soil, so it might stay around better than a place with more porous soil.

The reason for this is that the tree's natural capillary action draws water from the base, not from the crown.

This is an interesting theory. I know some Japanese carpentry methods take pains to ensure wood parts are oriented right side up and even sometimes with the cardinal directions to prevent warping. However, I understand that while transpiration moves water overall from the ground to the air, I remember reading that sap/water flows both up and down the trunks of trees. I remember reading that the old phrase "saps a risin'" for expressing the time to tap maple trees is actually backwards as the sap is actually flowing downwards. I do know that either end of a piece of wood will absorb water. Maybe a test would be possible with dye to see if one end absorbs better. There could always be some other factor at play as well making an upside down post last better if people have experienced it.

Jordan Holland wrote:I remember reading that sap/water flows both up and down the trunks of trees. I remember reading that the old phrase "saps a risin'" for expressing the time to tap maple trees is actually backwards as the sap is actually flowing downwards.

This is my understanding as well.  The reason you tap maple trees when you do, with daytime temperatures above freezing and nighttime temps below freezing, is that causes the sap to rise during the day and return underground at night.

Glenn Herbert wrote:I think a major reason for putting posts upside down relates to driving them in; the small end going in first will be easier and make the newly driven post more solidly set. There is also more thickness at the top for striking with a maul. If setting in a dug hole and backfilling, I would probably put posts base down for greater strength at ground level.

I agree about sap flow; it flows both up and down in the live trunk.

I'm not sure if this is the right place to ask, but how important is it to strip the bark off the pole?

That may depend on how rot-resistant your wood is; the faster it rots, the more important it would be to strip bark.
Bark will hold moisture near the wood after rain or whatever, and the area where this would make the biggest difference would be near ground level. Higher and the bark will dry out faster and eventually have no impediment to falling off, below grade (if your soil tends to be moist much of the year) it will be constantly moist no matter what you do to the bark. It may be that leaving bark on underground gives nutrients for rot organisms, I haven't studied that. I would concentrate on stripping bark within a foot of what will be ground level after the post is in place, and under the mounts for wire insulators or rails if you will have those.

I have wrapped bottom of post in plastic bags and tied tight. Increases post life dramatically.