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What is spalting ?

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Forum topic by coloradoclimber posted 1817 days ago 5216 views 0 times favorited 19 replies Add to Favorites Watch
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coloradoclimber

548 posts in 2694 days


1817 days ago

Topic tags/keywords: question maple spalted spalting

I’ve been working with some spalted maple lately and posted some projects, tapered box and letter box. It was commented that maybe the wood I was using was ambrosia maple instead of spalted maple. I did some “quick” research and this is my conclusion. I’m interested if anyone else has more specifics or wants to weigh in.

After some “quick” research, so don’t hold be too strongly to this:

I could not find a formal definition for spalting but the consensus seems to be something like:

Spalting is any form of wood coloration caused by fungi.

and

Spalting is caused by the infections of wood with various kinds of white rot fungi. The characteristic blue-black zone lines of spalted wood form when incompatible colonies of fungi come into contact with each other and lay down barriers to separate their territories.

I also read:

Ambrosia beetles are beetles of the weevil subfamilies Scolytinae and Platypodinae (Coleoptera, Curculionidae), which live in nutritional symbiosis with ambrosia fungi and probably with bacteria. The beetles excavate tunnels in dead trees in which they cultivate fungal gardens, their sole source of nutrition. After landing on a suitable tree, an ambrosia beetle excavates a tunnel in which it releases spores of its fungal symbiont. The fungus penetrates the plant’s xylem tissue, digests it, and concentrates the nutrients on and near the surface of the beetle gallery.

So based on this my take is spalting is the more general term. A fungus discolored wood is spalted. How the fungus got there is more specific. It sounds like the ambrosia beetle carries a particular fungus that it likes and that fungus causes splating. From my read it doesn’t sound like the boring so much causes the discoloration as the fungus spores carried along by the beetle as it bores around.

So I would say this maple is spalted. It may be the particular spalting comes from the fungus carried by the ambrosia beetle so it might be more precise to say ambrosia maple but my read is that spalting is a more general term and is correct.

An interesting side note:

Dark dotting, winding lines and thin streaks of red, brown and black are known as zone lines. This type of spalting does not occur due to any specific type of fungus, but is instead an interaction zone in which different fungi have erected barriers to protect their resources

Also known as sapstain, or in its most common form, bluestain, this type of spalting occurs when the darkly-pigmented fungal hyphae grow in the sapwood parenchyma of a tree


19 replies so far

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jerryz

164 posts in 1905 days


#1 posted 1817 days ago

And thank you for the information, now we know better….

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jockmike2

10635 posts in 2873 days


#2 posted 1816 days ago

You can also develope an allergy to spalted maple or spalted anything because it is a fungus. You can get it in your lungs, eyes or on your skin. Seldom is it a problem to people, but people with weakened immune systems or people susceptible to fungal infections are at risk. I read an article in which an older wood turner died from years of exposure to spalted maple.
Of course these things can be avoided wearing proper breathing apparatus and clothing.
Just a heads up. Mike

-- (You just have to please the man in the Mirror) Mike from Michigan -

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hObOmOnk

1380 posts in 2754 days


#3 posted 1816 days ago

The term “spalt” is a colloquial corruption of the word spoiled; as in “The milk done spalt.”

Not all fungi are created the same, e.g. Aspergillus niger is a black fungus sometimes found in Spalted wood. Breathing the spores might result in a nasty lung problem called aspergillosis.

I work a lot with spalted wood, but do the processing outside and always wear a dust mask and cleanup before going indoors.
After the wood is sealed with a finish, the mold will be encapsulated and relatively safe.

Wood species that contain natural sugars seem the most likely to develop fungal spalting, such as maples, boxelder (The Ash Leaf Maple), hackberry, etc. Worms and beetles can also add their own artistic contributions.

I love spalt but respect its down side.
I often encourage the growth of spalt by burying wood in wet leaves and allowing nature to take its course.

Sometimes spalt is like finding a diamond in the rough.

-- 温故知新

View a1Jim's profile

a1Jim

112010 posts in 2203 days


#4 posted 1814 days ago

Wow interesting, I hope there’s not a pop quiz

-- http://artisticwoodstudio.com Custom furniture

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ShopMonkey

26 posts in 2083 days


#5 posted 1814 days ago

Just a thought but i do not believe that that is spalting. those look like recovered worm holes to me. I work with alot of spalted woods and true spalting is typically lines and not patches. Still very beautiful though.

-- I like trees ...... as long as their by the board foot.

View mmh's profile

mmh

3382 posts in 2348 days


#6 posted 1814 days ago

And here I thought Ambrosia coloration was due to Ambrosia beetle poop/pee . . . aka “bacteria”, beetle sani-john.

It’s pretty wood despite the source.

-- "They who dream by day are cognizant of many things which escape those who dream only by night." ~ Edgar Allan Poe

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coloradoclimber

548 posts in 2694 days


#7 posted 1814 days ago

Seems there is still some question about how the discoloration got there and therefore what it might be called.

The conversation started in this thread and is still bouncing back and forth.

There does not seem to be any question about the beetle or worm holes. The question becomes is the discoloration caused by fungus or something else. If it is caused by fungus is it correct to call it spalting. The general definition of spalting would seem to cover it. If the discoloration is something else then it sounds like it would not be spalting. Or another point of view is that even if it is caused by fungus and would be covered by the term spalting the more precise and useful name is ambrosia maple to encompass the spalting and the worm holes.

So far I cannot find anything that definitively contradicts the idea that the discoloration is caused by fungus. Fungus introduced by the ambrosia beetle but still fungus caused. But without a concrete answer there are multiple opinions.

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ShopMonkey

26 posts in 2083 days


#8 posted 1813 days ago

but hey either way it is good looking stuff.

-- I like trees ...... as long as their by the board foot.

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TheWoodenBox

167 posts in 2235 days


#9 posted 1813 days ago

Here is what I found

Spalting is divided into three main types: pigmentation, white rot and zone lines. Spalted wood may exhibit one or all of these types in varying degrees.

Pigmentation
Also known as sapstain, or in its most common form, bluestain, this type of spalting occurs when the darkly-pigmented fungal hyphae grow in the sapwood parenchyma of a tree [1][2]. A visible color change can be seen if enough hyphae are concentrated in an area [3]. These pigmentation fungi often colonize wood via the rays, but are not considered decay fungi due to their non-destructive use of easily available wood carbohydrates [4][5]. The most common groups of pigmentation fungi are the imperfect fungi and the Ascomycetes [5]. Mold fungi, such as Trichoderma spp., are not considered to be spalting fungi, as their hyphae do not colonize the wood internally.

While pigmentation fungi do not degrade the wood cell wall, this type of decay can lead to a reduction in toughness (amount of energy absorbed before breaking), and increased permeability [6]. Pigmentation can occur on both hardwood and softwood, unlike other types of spalting which are more host specific.

White Rot
The mottled white pockets and bleaching effect seen in spalted wood is due to white rot fungi. Primarily found on hardwoods, these fungi ‘bleach’ by consuming lignin, which is the slightly pigmented area of a wood cell wall [7]. Some white rotting can also be caused by an effect similar to pigmentation, in which the white hyphae of a fungus, such as Trametes versicolor (Fr.) Pil., is so concentrated in an area that a visual effect is created [8].

Both strength and weight loss occur with white rot decay, causing the ‘punky’ area often referred to by woodworkers. Brown rots, the ‘unpleasing’ type of spalting, affect these same properties, but at a much faster rate [3]. Both types of rot, if left uncontrolled, will turn wood useless.

Zone Lines
Dark dotting, winding lines and thin streaks of red, brown and black are known as zone lines. This type of spalting does not occur due to any specific type of fungus, but is instead an interaction zone in which different fungi have erected barriers to protect their resources [5]. The lines are often clumps of hard, dark mycelium, referred to as pseudosclerotial plate formation [9].

Zone lines themselves do not damage the wood. However, the fungi responsible for creating them often do.

Conditions
Conditions required for spalting are the same as the conditions required for fungal growth: fixed nitrogen, micronutrients, water, warm temperatures and oxygen [3][10].

Water:

Wood must be saturated to a 20% moisture content or higher for fungal colonization to occur. However wood placed underwater lacks sufficient oxygen, and colonization cannot occur [6].

Temperature:

The majority of fungi prefer warm temperatures between 10 and 40°C [6], with rapid growth occurring between 20 and 32°C. [11]

Oxygen:

Fungi do not require much oxygen, but conditions such as waterlogging will inhibit growth [12][13].

Time:

Different fungi require different amounts of time to colonize wood. Research conducted on some common spalting fungi found that Trametes versicolor, when paired with Bjerkandera adusta, took 8 weeks to spalt 1.5” cubes of Acer saccharum.[14] Colonization continued to progress after this time period, but the structural integrity of the wood was compromised. The same study also found that Polyporus brumalis, when paired with Trametes versicolor, required 10 weeks to spalt the same size cubes.

Commonly Spalted Woods
The Ohio DNR found that pale hardwoods had the best ability to spalt [15]. Some common trees in this category include maple (Acer spp.), birch (Betula spp.) and beech (Fagus spp.).

Common Spalting Fungi
One of the more tricky aspects to spalting is that some fungi cannot colonize wood alone; they require other fungi to have gone before them to create more favorable conditions. Fungi progress in waves of primary and secondary colonizers [2], where primary colonizers initially capture and control resources, change the pH of the wood and its structure, and then must defend against secondary colonizers that then have the ability to colonize the substrate [2][16].

Ceratocystis spp. (Ascomycetes) contains the most common blue stain fungi [17]. Trametes versicolor, (Basidiomycetes) is found all over the world and is a quick and efficient white rot of hardwoods [2]. Xylaria polymorpha (Pers. ex Mer.) Grev. (Ascomycetes) has been known to bleach wood, but is unique in that it is one of the few fungi that will erect zone lines without any antagonism from other fungi [18].

View LittlePaw's profile

LittlePaw

1571 posts in 1704 days


#10 posted 1135 days ago

Wooooooow! That, I’m afraid, is a little over the head of a simple old wood carver. But thanx for the info, just the same. As for me, I’ll just call it Spalted Ambrosia for simplicity from now on, if no one objects.

-- LittlePAW - The sweetest sound in my shop, next to Mozart, is what a hand plane makes slicing a ribbon.

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DrDirt

2405 posts in 2368 days


#11 posted 1135 days ago

It is rot – that looks cool until it gets too far along and your piece crumbles..

-- "If we did all the things we are capable of doing, we would literally astonish ourselves." Edison

View LittlePaw's profile

LittlePaw

1571 posts in 1704 days


#12 posted 1135 days ago

You mean the fungi keep eating the wood years after I’ve finished carving it – until it crumbles??? Now that ain’t cool! So how do you stop it?

-- LittlePAW - The sweetest sound in my shop, next to Mozart, is what a hand plane makes slicing a ribbon.

View Nomad62's profile

Nomad62

706 posts in 1584 days


#13 posted 1134 days ago

You stop it by drying the wood; fungi need wood to be somewhat moist, say 15% mc or so; most households are about 10% or less on average, so the spalting quits in such an environment. I read a paper on spalting from the U of Mass, saw it online somewhere; anyway, it stated that there are 3 fungi that get into wood, some more than others. The first gets in there and thrives, leaving behind a discoloration of the wood but does not degrade it; the second can only enter after the first has been there, as the firsts waste feeds the second; the second degrades the wood, and the first doesn’t tolerate it so it builds the black wall of defense between themselves and the second fungi, seen as a black line when cut thru. The third fungi is a white rot version, which only comes in after the second and totally destroys the wood. So my opinion (I know you are all waiting for it, lol), based on that there paper, is that “spalted” is best defined as a condition of the wood.

-- Power tools put us ahead of the monkeys

View LittlePaw's profile

LittlePaw

1571 posts in 1704 days


#14 posted 1134 days ago

Okay, I’m keeping all my wood, especially the spalted, in the garage where it is HOT and dry! I know I can’t stay in there for long, so the “funguy” probably couldn’t survive either. Thanx. Do you know what the male fungus said to the femalel fungus? “I’m a funguy!” Well, at least it’s clean!

-- LittlePAW - The sweetest sound in my shop, next to Mozart, is what a hand plane makes slicing a ribbon.

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LittlePaw

1571 posts in 1704 days


#15 posted 1134 days ago

Aaaaaaaah Soooooooo! Belly interstink and getting pretty deep! LOL :}

-- LittlePAW - The sweetest sound in my shop, next to Mozart, is what a hand plane makes slicing a ribbon.

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