What is spalting ?

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

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

-- Mike. mwurm13@yahoo.com

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.

-- Randy, Rustic Artisan, a family tradition. (No PM's - auto-deleted.) - "I am a seeker, not a follower."

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

-- Jim from Heirloom Woodshop Southern Oregon

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.

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

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.

but hey either way it is good looking stuff.

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

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].

-- Twenty years from now you will be more disappointed by the things that you didin't do then by the ones you did. - Mark Twain