I inspected a house today and there was a dead tree with these on it. I live in NY.
I don’t know whether this is anything with insects or not.
Thank you for you help!
2 Likes
Sorry, I can’t help you with that, But Welcome to the forum, Sewoong. Enjoy!! 
1 Like
You mean the black stuff? Is is tar?
If so, it’s tar used by arborists to protect the wood of a ex-branch from rot.
The middle picture in particular looks like just that.
If not tar, could you describe in more detail and get a closer up?
Oh, yes.
Use of tar… not necessarily a good idea
"Trees have been around for around 360 million years and managed quite well without our “help”. "
1 Like
Maybe knocked off some Chaga mushrooms, for their medicinal purposes, and sealed the wound like Bryce said…
1 Like
Does it really matter? The tree is dead (as you stated) and it’s time to be removed!!
3 Likes
Black Knot Fungi
3 Likes
Does it really matter? The tree is dead (as you stated) and it’s time to be removed!!
In some cases, a the wood from a diseased tree may be quarantined. For example with the emerald ash borer. If the tree above is (was) an ash, and the canker is EAB, the issue is present:
While the insects don’t move far on their own, people unknowingly transport infested [fire] wood to non-infested areas. Since its discovery in Michigan in 2002, EAB has killed tens of millions of ash trees It has spread to Illinois, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Missouri, New York, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and Wisconsin. All of Virginia is in the federal quarantine area.
You can note what you saw, describe the potential for spread of disease, and refer to an arborist or tree removal company.
Oh, I don’t know. But, it could be… 
1 Like
Tried to edit and ended up deleting. So here’s the repost…
The sizing of it is all wrong, and the geographical location even more wrong (like ridiculously so, as the only poisonwoods I’ve ever encountered were in Central America), but it looks like poisonwood sap to me, or at least the early start of sap ‘healing/protecting’ itself.
Not at all arguing with other responses, as they very well could be right, but pruning paint (tar) should be noticeable based on application approach (and that looks natural in the picture), and I’m pretty sure that black knot only hits fruit trees (and that looks way bigger than a fruit tree).
1 Like
We have hemlock trees up here in MI.
2 Likes
Thank you every one!
I will make a note of it.
I did not find any signs of wood destroying insect on the house structure. However, on backyard, I found rotten retaining walls and fence, and a dead tree like this. To me it looked like a nest of some insect. I did not want to scare the client and wanted to make sure what it is before I write the report.
How close was the tree from the OP to this wall? Don’t see a lot of creosote treated dimensional, but that could be the answer to both questions.
And is that volunteer bamboo growing?
that is incorrect
1 Like
I watched Flash Gordon and I would not stick my hand in there.