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I am interested in taking steps to ensure that some timber that I am drying does not develop spalting.

My specific scenario is as follows:

  • Recently felled Maple (1-2 months ago),
  • Whole logs with bark retained on full circumference,
  • Sizes from 1" to 5" diameter,
  • Currently stacked with air gaps allowing circulation around all pieces,
  • Stored in dry concrete basement with steady warm temperature,
  • Goal is to dry logs/branches whole with bark for craft work.

Someone looked at this setup and told me that spalting was probably unavoidable in the larger peices, but I find that doubtful. Is it unavoidable? Have I done what I can do already?

The broader question here is what steps should one take to preclude spalting when drying wood? If my specific scenario helps provide context to answer that question, good.

  • I don't know that it's right to say it's 'probably unavoidable' but the length of time wood is wet is a key factor. For the smaller diameters I doubt you'll have any trouble at all avoiding it. The pieces ~6" are going to take a very long time to air-dry however ....as much as 4-6 years since you should coat the end grain with something (molten wax is good) to slow the drying, to minimise/prevent various kinds of cracks forming. – Graphus Jan 15 '16 at 11:20
  • As I researched the term spalting, I saw that there is a market for just that. When is it best to avoid spalting, and when is it preferred? – Nachmen Jan 20 '16 at 10:30
  • @nachmen That might be a good new question! – J Walters Jan 20 '16 at 12:38
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The broader question here is what steps should one take to preclude spalting when drying wood?

Spalting, as you probably know, is the result of fungal attack on the wood. Wikipedia lists several conditions that need to be met for spalting to occur:

wiki snip

Thus, if you want to preclude spalting, do the opposite of the things listed above.


Since you are attempting to season whole logs, they will retain water much longer than if it were sawn and hence be susceptible to fungal attack for a longer period of time.

If you keep air circulating around the entire log to quickly get the moisture content down, it might reduce the risk of spalting. That's a double-edged sword because rapid drying leads to rapid cracking of the log cross-sections. However, you state that you have

Whole logs with bark retained on full circumference

which will not help drying at all. Bark helps the tree retain moisture and greatly slows air drying.

If it were possible to place the logs in a totally oxygen-free environment, that would probably be your best bet. However, I doubt you have the ability to do that (unless you happen to live in a submarine or have access to a magical air-tight workshop and can work wearing an oxygen mask).

There might be a fungicide you can apply to the logs, but this is just speculation on my part. I've certainly never heard of one.


I would like to note that the Wikipedia article references a paper on spalting of sugar maple that may be of interest, if you feel like going through the trouble of acquiring it.

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Moisture is the largest contributor to wood spalting, especially maple. However, what you are doing will greatly reduce the risk.

The only wood I have used so far that has spalted when kept in a dry place is my yellow birch. The bark is too good at preventing moisture from leaving the wood.

Maple, especially the small stuff you have (under 6"), really shouldn't have any issues with spalting if you cut it an have it drying right away. One thing that could help even more is if you have a dehumidifier in the basement with the wood (at least in the damper parts of the year). This would help remove more moisture.

Now after all that is said and done you want these pieces to be used whole, with the bark on, so even if by some strange chance that they spalt a little, no one will see, notice or care if you are keeping them as such.

A more likely issue if these logs are longer, is splitting as it dries. I had a 6' long piece of maple about 6-7" diameter and let it dry, it split all over the place, but it didn't spalt at all.

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  • Good idea with the dehumidifier. Also, having "spalt" and "split" in the same paragraph is really confusing to my eyes :-) – grfrazee Jan 14 '16 at 16:32
  • @grfrazee Not to mention that spalt isn't in chrome's dictionary, so it always has squigglies... – bowlturner Jan 14 '16 at 16:47
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Having now dried the above described wood for a year I wanted to share my results from the steps that I took to avoid spalting.

The wood included maple, poplar, and other species of 1" - 6" diameter.

I took the following steps avoid spalting:

  1. I cut the wood green and immediately brought it inside to dry.
  2. The wood was stacked in criss-crossed layers to aid in air exchange and moderate stagnation.
  3. The basement was heated in the cold months by a coal furnace (used to heat the house above, but gave off lots of radiant heat for the basement). I would estimate the typical temperature at around 75°F.
  4. The basement was naturally dry and a dehumidifier was also used to further maintain the low humidity. I would estimate the typical RH at 35%.

I have now cut into many of the pieces up to 5" in size and have observed little or no spalting. Some of the bark had separated in a few places on some pieces. However, with the exception of the expected end-checking, no other negative effects of the drying process were observed.

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  • 2
    Good to hear your experiences after a suitable time gap but this isn't an Answer and SE has a strict Q&A format. This additional info should ideally have been edited into the original Question as is often done when follow-up info is being given by the OP. – Graphus Jan 28 '17 at 10:08
  • @Graphus Respectfully, I disagree. This is an answer, and demonstrably so. Experiential evidence is entirely admissible. I encountered a potential problem and asked for steps on how I might avoid it. A year later I came back and offered the steps I took with the result of avoiding it. These steps are entirely supported by the more generic scientific evidence provided by the other answers. My answer provides a very specific answer to this question and is entirely within the guidance of the Help Center. Meta may have something further to add, but I am not aware of it. – J Walters Jan 28 '17 at 14:30
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    I'm not one to discount anecdotal/experiential evidence, quite the opposite in fact, but I still think this follow-on info, based as it was on the Answers received initially, would be better edited into your original Question. – Graphus Jan 28 '17 at 17:59
  • My answer is not, in fact, based on any answers already given—though it does seem to offer concurrence. When I asked this question I had already set up the drying conditions and didn't change anything for a year. The other answers offer helpful theory; my answer offers actual practice. Answering your own question is encouraged on SE. If you think my answer is an exact duplicate I would encourage you to flag it for review. – J Walters Jan 28 '17 at 18:10
  • This is only a single trial, not rigorous proof, and cannot necessarily be readily reproduced by others in order to stand on its own as a reliable and practical spalt-free drying solution. "I would estimate the typical..." doesn't suggest that you monitored and recorded the conditions very closely, though perhaps you did. If you had performed the same test to various similar samples of timber subjected to varying conditions and periodically recorded moisture content and other variables, this would be much more valid. – rob Jan 29 '17 at 21:24

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