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I have a PhD in Forest Science and professionally research the interaction of fungi on wood for the value-added wood process of spalting.
Is there any way to generally classify the fungus by discoloration?
Yes, but the key word here is 'generally'. Bleaching is caused mostly by basidiomycete (wood decay) fungi, so if you see punky white areas, you can hold fungi like Turkey Tail as suspect. Pigments are usually from ascomycetes, and depending on the color, you might be able to narrow it down a little more. For instance, there is only one genus that makes the blue-green color: Chlorociboria. It is mostly Ceratocystis and Ophiostoma fungi that make blue stain.
For zone lines, you're out of luck. Many, many fungi have the capacity to produce them either alone or from external antagonism. So unless you see Dead Man's Finger growing somewhere near the wood, you really have no way of knowing what caused the zone lines.
In general, zone lines indicate white rot decay. So in that sense, yes, wood with zone lines is much weaker than sound wood. Unless you have intentionally spalted your wood with Dead Man's Finger, which is only slightly destructive, its a good bet that some areas of the wood are very punky.
Never fear however! While zone lined wood found outside may be too soft to turn, most anything you spalt at home will still be mostly sound if you've controlled the conditions well.
Sorry mvealey, I only just noticed your comment today! In response to your questions, yes, you can store fungi for later! The fruiting bodies themselves may not keep, but a piece of actively spalting wood will. I suggest sticking it in a ziplock bag and putting it in your fridge (for long term storage) or freezer (for short term, and no, those aren't backwards). The cooler temperatures put the fungus in stasis, but it will be easily revived once you warm it up.
The cutoffs you mentioned may be useful, and they may not be. If the cutoffs are still green then there is a good chance that the fungus is still active. If they're dry, you'll need to test them. Get a plastic bin with a lid and stick your pieces inside. Splash some tap water over the surface 2-3 times over the next week. After about 10 days, see if any mycelium is growing on the surface (it should be white. If its green, thats just a surface mold, and completely useless in terms of spalting). If no mycelium grows then your spores are probably not viable anymore. If it does grow, stick it in with some wood you want to spalt, and make sure everything is nice and wet.
Let me know how it goes!
I think you missed a lot of the main points in the article. The point I was trying to make was that spalted wood can be an issue, but the main cause of respiratory and eye problems in woodworkers is actually wood dust, not spalting. It is true that your spalted wood could have had some bad fungi on the surface that caused your eye condition. However those fungi were not DECAY fungi, the fungi that cause spalting. More than likely they were simply mold spores that landed on the wood from air circulation.
Not more than an hour ago I left a meeting with a top mycologist for the Forest Service. We discussed spalting and the possible toxic effects it could have. She brought to my attention that even those black mold spores were actually debunked as causes for the respiratory diseases that develop. In the end, the culprit was straight asthma and allergies, and nothing actually caused by the mold spores.
The issue with 'ask any doctor' is that doctors are not mycologists. Doctors are familiar with general practice, common conditions, and molds/fungi which cause diseases in humans. They are not familiar with wood-inhabiting fungi, which are the fungi we deal with when spalting. In this particular case, I would suggest that you 'ask any mycologist', especially those familiar with Basidiomycetes (wood decay fungi).
To everyone else who has concerns, I invite you to e-mail me at firstname.lastname@example.org. I've sent out several very detailed e-mails over the past several months that list common spalting fungi, and links to scholarly articles which discuss their toxicity towards humans (or lack thereof). I stand by my statement that there is no special danger in working with spalted wood unless you have a compromised immune system (this includes asthma and many allergies!). I am violently allergic to wood dust (and all fine particulate matter) and many fungal spores, but work with spalted wood with no ill effects.
For more information on the general toxicity of wood dust, I suggest this article by OSHA:
Wurmm, I appreciate your concern, and would be happy to address any other concerns you may have regarding spalted wood.
Yes, spalted wood is safe for food contact. As with any wood, spalted or not, the key is to keep the bowls dry. If they need to be washed, a wipe with a wet cloth and then a prompt drying will keep any new fungi from colonizing.
To be on the safe side, I would suggest you keep your stock in a rotation, where the ones you sell have been sitting in a well-lit room for 4-6 weeks before being used for food. Fungal spores can remain viable for quite a while and will grow again if given the option. However, this is not a phenomenon unique to spalted wood, as all wood has fungal spores on it, regardless of whether or not it is spalted.
I would also recommend changing your finish to a salad bowl finish or urethane oil. Wood in food contact should be treated with a penetrating finish that will seal the vessels and prevent cracking due to moisture changes. My two favorite finishes can be found at:
(both from www.woodturnerscatalog.com)
I'd be far more concerned about the fungal spores in your woodshop that you breathe in every day than ones that might get into your gut. Fungi require oxygen to survive, and the stomach is not only highly acidic, but also anoxic. Your lungs, on the other hand, are a little bit of a nicer area. But before you panic about that, rest assure that unless you have an immune deficiency of some type, the spores are no more harmful than wood dust.
I'm planning a blog entry on this topic soon, so keep a look out.
nosepikr: I'm familiar with the beetle problems you guys have out there. Yes, that blue staining you see is spalting. There is some fascinating literature available on how the blue stain gets into the wood which you might be interested in reading:
Basically, the beetles carry the blue stain spores on themselves. When they infect a tree, the spores tag along for the ride, and get free access to the inside of the tree.
As for sealing blue stained wood, you have some decisions to make. Most spalting colors fade under direct sunlight. There are UV protectant finishes available, but most amber the wood. That isn't such a big deal if you're working with cheery, walnut or even maple, but if you're hoping to keep a strong color contrast on your white wood, you'll need to look elsewhere.
Personally, I prefer to use a paste wax for wood that will not be under heavy use, and a water-based polycrylic (many are produced by MinWax) for heavy use applications. Neither amber the wood, and both produced substantially fewer toxic fumes as you apply them.
Mayonaise eh? I'm not sure I would recommend this approach, as none of the components of mayo are of interest to the fungi (except maybe the sugar). I'd be interested to see his spalting timeline when using mayo versus not using mayo. Anyone else tried this and had it work?
Miserybob, those are a lot of long answer questions. If you don't mind, I'll save those questions and answer them in my next few blog entries. They deserve more time than a posted comment!
In general though, the spalting stops when you drop the moisture of the wood below a certain level (air dry is too dry for fungi). The fungus can't be active without water, so it is dormant. Finishing seals the spores into the wood and cuts off air flow to the remaining fungal hyphae (the 'roots' of the fungus), which also stops growth. Properly sealed spalted wood is perfectly safe for normal uses!
Those white fans are known as a 'shelf fungus', and are usually great spalters! You should post some pictures of the fans and the wood. Some of the fans, like Trametes versicolor (Turkey Tail) are some of the quickest spalting fungi around.
Unfortunately, there are a lot of fungi that can grow on roof shingles. Could you give me some more information so I can narrow it down a bit? For instance:
What type of wood are your shingles made out of?
What color is the fungus?
Does it form a fruiting body (mushroom)?
Unless you actually have the old type of solid wood shingle, I'm betting that what you have is algae, not fungi. Algae don't work for spalting, but they can certainly make your roof look pretty nasty!
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