White birch question

[Kevin]

What is this black on white birch trees?

[deeker]

Looks like black stuff.
Honest.   
Our quakie aspen has it too, an injury?

Kevin

[thecfarm]

Not a cross beween a gray birch and a white birch tree is it? Some of mine had it.I had it on mostly my old trees,60-80 years old.

[roger 4400]

    Hi ! To me, it looks like a gray birch.....and those *triangulars black marks* are old limbs marks. It,s young but I could not see any bark peeling on the trunk like white birch do.                      See you                                  Roger

[Kevin]

It could be a gray birch, I didn't see the specific tree and didn't know we even had gray birch in this area so I'll check with the guy that was asking me about it.

Thanks!


:Gray Birch appears South and East of the Great Lakes Region

http://imfc.cfl.scf.rncan.gc.ca/arbre-tree/feuillus-deciduous/bouleau-birch-eng.html

[SwampDonkey]

Looks to me like a healed over branch knot, no matter what birch it is. The other black marks could be where outer bark peeled away to reveal inner bark, which turns black with age. Grey birch does not peel readily like white birch does and the branches are wirey in appearance. I wouldn't expect grey birch up where Kevin is at, it's mostly a Maritime lowland tree and upper St Lawerence east of Lake Ontario. Talking about Canadian range here.

[Kevin]

Donk;
What would the black be, some type of mold?

[SwampDonkey]

I would say so. If it starts weeping sap, nectaria fungus likely has hit it to cause target canker. Common even in yellow birch and aspen. Not sure if bronze birch borer helps the infection or not.

Going beyond the thread a bit:
Birch dieback is another disease, but little understood about. It wiped out our big birches of both white and yellow birch back in the 40's. It wasn't just a tree here and there dying of old age, the whole bunch died off in short order. It's more devastating up here in Canada because the white birch is more of a northern tree. I've seen good sized old birch up here in northern New Brunswick, but in the south I don't see much of any bigger than 10 inches and they get a lot more grey birch down there because it's so wet and low. The woods look kinda sick in the lowlands.

[Kevin]

Thanks Donk!