Cutting and Drying a Walnut Stump

Tips and tricks for sawing stumps for lumber. January 14, 2009

I am digging out the stump of a recently cut walnut tree to experiment with in my wood working. I need some guidance to cut and dry to wood to minimize cracking of the wood.

I have the following questions:
1. It is July. To minimize cracking of the wood during ambient air drying is it better to wait until later in the year to dig out and cut up the stump? If so when?

2. To avoid cracking of the wood pieces I am planning to use parafin wax. Do I need to coat the entire piece or just the end surfaces?

Forum Responses
(Sawing and Drying Forum)
From contributor V:
I am assuming you are going to slice it? What thickness? Is the wood solid? I have had good success in drying this sort of material, but I need some more details.

From contributor K:
The stump is solid and is from a very large tree. The diameter of the cut surface at the top of the stump is 29 in. and is about 3-4 feet in height to where the last of roots branch out. It has five roots that are 12 to 18 inches in diameter. I am undecided as too how to best use the stump. I have considered slicing it into 2 to 6 inch thicknesses, the larger for use in turning into bowls or lamps.

I was advised to remove it intact and paint the cut surfaces and to then let it dry as a whole piece. This is my first experience with this and I will be grateful for advice from anyone who has had experience.

From contributor S:
That sure is an unusual project! I'd go ahead and dig it out now and get it sliced up ASAP. Then go ahead and wax the ends and keep the wood in a place where it won't dry out too fast.

If you're not going to slice it up now, leave it in the ground. But if you leave it there too long, bugs might be a problem and the top of the stump will start drying out and cracking. Maybe you could put in some pictures to show what the grain looks like when you get it sliced up?

From contributor E:
I would not leave it whole to dry (unless you have ten years to wait). There will be, of course, all kinds of stress wood in there. I've discovered a few tricks to dry this kind of material with any success.

1. Cut it to size, and Anchor Seal/Wax the ends and a thinned application of seal/wax on the surface. Shellac is also a good option for the surfaces.

2. Coat the whole thing in WoodJuice from Preservation Solutions. It is not cheap but it works. Apparently it keeps the cell-structure from collapsing during drying, thus allowing the internal to dry while the outside remains intact (cells do not shrink). If I have "trouble material" that is valuable and/or important to me, this is my choice.

3. A third option, which the above respondent mentioned was to slow the drying down (essential what #1 is doing). I've had good success in drying walnut crotches in my below-grade (damp) basement.

In summary, it's a cost-benefit analysis you must calculate. #2 is most costly but almost a sure bet, #1 is very good but slower and more risky, #3 is easy and costs only some sweat, but is also slow!

From contributor A:
Sawing stumps is hard work. You will have to pressure wash it a lot and there are still pockets of ingrown dirt and rocks so plan on ruining some blades. It is best to get it washed and sawed as soon as it comes out of the ground. I have found that completely covering the wood with Anchor Seal is best and slow drying are key. Most are split with a chain saw and then put on the mill. Cutting large chunks is best as they can be re-sawed later.

From contributor D:
I agree with what contributor A said. I have done it a few times. I would suggest letting it soak in a pond for a while to clean it some if you can.

From contributor B:
Would a closed in shed be ok for air drying something like this? Would less air moving around slow the drying or would it cause problems. I have a room that’s empty and dark with a dirt floor. Would that be a good place to air dry wood like stumps or crotches? Would you install a fan or two?

From contributor E:
Sounds like that would be ok. I would not use a fan, however. Also, "damp" is a relative term: real green wood will dry somewhat in real humid conditions. Once it equalizes, it will have to become less humid to dry it further. I know some folks cover their green material with Tyvek house wrap to slow drying down. Your absolute best scenario is getting it into a kiln where you can control both the temp and the humidity.

From contributor B:
You are supposed to dry figured wood like what is in stumps and crotch's a lot slower than plain grain lumber of the same species right? And if the max % removal per day is 8% for normal walnut would you slow it down to where you are just removing 2 or 3 % a day? Some other %?

If you were going to put it in the kiln right after sawing you would pass on the watered down coat of anchor seal on the surface, right? I have a walnut stump coming soon too.

From the original questioner:
I appreciate each of your responses. I am fortunate that this stump is in clay soil with no rocks and so it is not as hard on my chainsaw as it might otherwise be. I'll sharpen my chain saw as often as needed. I plan to cut it into large pieces as suggested. I'll probably try to do this all with my chain saw and not put it on the mill. I have an air conditioned basement where I'll dry it and will Anchor Seal/Wax the ends and other surfaces. I am not sure where to find the WoodJuice.

I have a couple of additional questions:
1. In slicing it up, what are the best size pieces to make for slow drying and then re-cutting? Am I better off to cut them vertically as long as possible and leave them in 6 to 8 inch diameter pieces or to slice it horizontally in certain thickness and leave these pieces to be re-sawn later?

2. What about the roots? Should I not worry about keeping much of the root ends on the pieces? That would be easiest but if they are valuable to an experienced wood worker I would try to leave them?

3. When you say stress wood I assume you mean the areas that will have interesting and unusual grain. Will that be in the center of the stump or where the roots branch out and therefore throughout the stump?

It is interesting as I have sliced through several of the roots. When first sliced they appear to be the color of sap wood. At further inspection several days later the walnut color appears to be moving into the cut ends and coloring the wood. Are these large roots of value to turners if they are 10 to 18 inches in diameter and should I try to cut them out and dry them also?

From contributor K:
I have only done one, and I think that will be all I ever will do. To me, your tree sounds too small to have much of what you are after. The best figure will be on top of where the root buttresses are. The space between or down the center of the trunk are not worth any effort.

Before you put much effort into this, I suggest that you take a hammer and knock some of the bark off of the top of the turn of the roots. This will give you a good look at the figure that you can expect. If there is a lot of wild amazing figure that you can't stop yourself from going after, then go for it.

If it is just sort of ok, you can find easier firewood than rendering it from this. While you are sawing this wood out, start thinking of how you would like to use it, because of its nature, it may not be all that easy to just work into any project that comes along. Long thin sweeping curves with a lot of grain run-out may look nice but won't have much structural strength. Also planks with the curve in the longitudinal axis make for a tendency to warp in drying, or poor glue up properties for panels.