Yes, every wood has the potential for spalting, however some wood species are more susceptible to the fungal attack that creates the patterning. Both hard and soft woods can be spalted, and the availability of each of these comes down to the typical location where that particular tree grows naturally.
Softwoods will spalt quickly while hardwoods will take longer but this allows us as wood workers to step in and use the hardwood before the wood is useless from the decay that the spalting process is a part of.
Softwoods will transition from useful wood to useless wood very quickly and it is difficult to catch it at the right time. Hardwoods allow more latitude.
If you decide to make your own spalted wood, you will discover exactly what we are talking about with regards to the window of opportunity. The take away here is that by mimicking the natural spalting process we can manually engineer a spalted wood piece with some practice and patience.
How do you get wood to spalt?
To spalt wood, the log needs to be in contact with the ground to be sure that the fungi spores have unfettered access to the wood. It doesn’t seem to matter if the log is laying down, or a section of it is standing and in contact with the soil. This method does create some rot at the soil contact face but it can be controlled with care.
The environment needs to be moist and warm for the spores to become activated. How we go about making spalted wood is we take a section of a log and we stand it on one end and leave it for a season . The location is in the shade, and the ground is often moist but not damp.
We live in a tropical zone so there is plenty of fungal spores floating around all the time, and because of the year round warmth we can have the fungal activity active throughout the year if we need it. In dry times we have placed wood shavings on the top face of the logs to maintain some moisture in the log and to get the fungal activity progressing from both ends.
How long does it take to spalt wood?
It can take up to a year for the spalting to do its thing, and the longer you leave the wood the more risk there is for the fungal decay process to take the wood past the point of being useful and into the rotten wood zone.
After a year the wood can be cut into the rough size you need and you can check the spalting at this time. If the result is not strong enough you can restack the wood face to face with some damp sawdust between the faces and this will allow the spalting to continue.
Cover the wood with a tarp or similar to maintain moisture. The spalting pattern will be changed because the fungi that is in the wood will likely be harmed in the cutting process so fresh fungi will take over from the original variety.
Can wood be over-spalted?
Yes, spalting can easily be taken too far and this can weaken the wood so much that the uses of that wood are now very limited. Any structural requirements should be avoided with this wood. To tell if the spalting has gone to far, take a pencil or similar and push the end into the wood.
The wood will be soft enough for the pencil to penetrate easily. Another observation is that the wood will be a lot lighter than a piece of the same wood that has no spalting. The wood will fracture across the grain as easily as it will along the grain, and it even “feels” soft and light.
Once the wood has reached this point, it will need to be stabilized if you want to work with this wood. Be aware that there are risks that come with working this type of decayed wood and some of these risks are covered in “Is spalted wood dangerous to turn?“. We recommend this article if you are a wood turner.
Can spalted wood be used like normal wood?
Spalted wood can be used any where standard wood is used but only if the spalting is stopped before the wood is weakened. If the patterning is heavy, we recommend that you use that piece for aesthetics and not as a structural member.
The patterning that we prize is the early sign of the fungi claiming that piece of wood as its own. The darker lines that separate the colors are delineation zones between different species of fungi and they act as chemical barriers for protection. This chemical protection is one of the risks we need to keep an eye out for as we work with this type of wood.
The wood worker looking for something different can start to explore the world of spalting, and over time, the enjoyment of creating an item from spalted wood that you played some part in creating is hard to match.
The fun thing is you never know what the pattern is going to look like. There are tree species that are well known for spalting and maybe this is because the wood hardness is just right, and the location where the tree grows has the right environment for the spores to inoculate the wood.
Trial and error is the name of the game if you want to try different types of woods.