Black spots in oak?

[kevin j]

I cut up some oak (don't know which variety) from the local city tree dump site. About 10 to 16 inch diameter pieces. There were occasional black spots, like spray paint dots, about 1 to 1.5 inch diameter on the cut faces I made, usually about 2 to 4 inches from the bark surface. Did some autopsy either direction and they seemed from 2 to 6 inches long (up and down the tree), and no lead or metal indicated. Part of the tree had oak wilt, but wood was green and there was good bark on the pieces with the black spots.

Good firewood, but I am really curious: what causes the black areas?

 

[svk]

Were the marks on one side of the tree or sporadically located?

 

[T. Mainus]

I've always thought that meant there was metal in the tree somewhere close by.

 

[Cody]

I've always questioned this piece of bur oak, wasn't anything like this?

 

[foeke]

There was a nail in it 30 years back

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[foeke]

I live in an area in Germany where the Americans didn't know for sure if they would "liberate" or the Russians. So the threw all the bombs they had left on anything that might contain hidden german weaponry (forrest next to a jugend ss location). Note after the war was over. All the oaks are filled with these spots from old grenade shells.

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[foeke]

The nail doesn't need to be in the neighbourhood. Could be meters further down.

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[farmer steve]

View attachment 566873

I've always thought that meant there was metal in the tree somewhere close by.

There was a nail in it 30 years back

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agreed that it is metal and you may find it when you split it.

 

[moondoggie]

Metal for sure.

 

[Guswhit]

I ran into one a few years ago that head been used as target practice. It had little spots like that from the lead bullets. I guess a reaction from the moisture in the tree as most of the lead was still intact.

 

[hedge hog]

It's a mold or a fungus


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[Ted Jenkins]

From my experience metal, mold or. I have encountered all of the above mentioned. Nails and screws were the most common. If you find a dark spot 4'' to 6'' in from the bark then you know that the item has been in the wood for perhaps 50 years. After 50 years the nail has long since disappeared from corrosion rust. Several years ago ran into some Oak that was eating up my chains so after investigating found some galvanized lag bolts embedded well into the wood. So was reminded to be careful. Have ran into wood with dark spots that turned out to be just remains of metal. One time found a bullet embedded near the center of a Oak that was close to 500 years old. Then another time found a completely usable come along in the wood. Looks like you found some great Oak cut it up with much joy. Thanks

 

[kevin j]

thks all.
svk steve: Can'ty recall where located if all on same side or not. Random rounds.
TMainus: yes thats what I saw.
Cody: not porous like your pic. Normal wood.
Guswhit: no lead or metal , I carved around quite a bit.
Hedgehog: would oak wilt do it?
Foeke: tree not that big for 30m yrs ago, no tissue damage or scarring around them in any way. Nothing found in the splits, but that is pretty small percentage of volume that would actually be exposed.

I think foeke has it. If the metal or lead can be somewhere else up or down the tree, good theory. Anytime I've seen marks it has been metal traces right in the marks areas. This looks like metal traces, just no metal, which is what has me curious. So there is probably metal somewhere else than shown.

thks to all for input.
kcj

 

[svk]

I was just thinking that if the stains were on one side it could have been shot with birdshot many years ago.

 

[hedge hog]

Oak is more likely to do it than any other
Had the same thing
Same post as you
You can look it up but some guy posted a link to the subject and is truly convincing
My bur oak tree was 56" and started at ground level and went 20' up into the trunk


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[Cody]

thks all.
svk steve: Can'ty recall where located if all on same side or not. Random rounds.
TMainus: yes thats what I saw.
Cody: not porous like your pic. Normal wood.

What TMainus posted is what I see when fence has been growing in a tree for a long time, I've even got some fence pieces as "souvenirs" by the stove from this winter. The picture I shared isn't a porous piece of wood. We still don't know what it is but it was like little knots throughout the tree, only noticed them when splitting and not when cutting into rounds.

 

[foeke]

It's the tanin in oak. That reacts with metal. The metal used to be in the sapstream. It might be corroded away. If it is bigger you would find the cause in the lowest part where one side has the dot, and the other doesn't. In this case, not very likely. You can also find it when halfway in the cut, sparks come flying by and after that, your chain can only produce wood flour.

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[Johnnybar]

Any way of knowing if the pieces were within 5-6' of the ground level? Something penetrated the tree years ago and either left metal or allowed fungal intrusion. Either of which can leave dark staining. I recently felled a live standing Red Oak that was full of lightening strike fungal spalting and a couple metal stains:

 

[hedge hog]

 

[Full Chisel]

Johnnybar, that is a gorgeous red oak!

I always hate finding blue spots in logs. My buddy called me last week to come out and cut up a white oak he had dropped in his yard. I was using the 390 with a 24" bar for the upper half of the trunk but decided to put the 36" bar on for the butt of the tree. One cut in and BAM...U bolt hidden in the bark. Brand new Stihl RSLF chain took a hit.