Why Knot?

I don't know whom of us is mistaking this tree, as it could be a matter of translation, but on your very site you can see the description and a picture of an acacia trunk:

And here, what a Poplar looks like:

francis I am inclined to believe that your tree is not an acacia. Can you scrounge up a few seeds or pods and some leaves from under the tree?
have the "leaves" always been that shape or was there a juvenile form of "leaf"
You are of course correct by saying that some acacias have a very long lifespan. Acacia melanoxyn *(blackwood) is a very good example living up to 100 or more years.
Is your tree deciduouse (do the leaves fall off in autumn) or evergreen?

The first tree pictured is not an acacia (alex's post). It is possibly an elm of some type. The infection is probably elm leaf beetle. Difficult to treat and the tree will eventualy die. Treatment involves injecting the soil to kill larvae.

francis's tree is not a poplar.

DP, the more I look at the original picture the more I believe it's what we call an Acacia.

Take a look here, on the leaves and flowers of that tree. I've many of them in my garden.

Acacia

They are obviously deciduous.

Last week they were under the snow and looked absolutely like the first picture.

to the best of my knowledge there are no deciduouse acacias francis? I need to do some domestic chores but I will return.
Acacia usually (in all but one case) has a feathery juvenile leaf.

As I said before, it's probably a matter of translation but I think I found the right tree, in English:

Black Locust

So I have looked at your link now francis.
Robinia is NOT an acacia. It is not even part of the mimosoides family although it does have the common name psudoacaia. (psudo means like or near to).
I think Robinia belongs to the fabiacea family.

Can you translate this for me francis? do it another time if you are busy. As an aside I am led to believe robinia wood is very beautiful

Utilisations : le Robinier émet des stolons grâce auxquels la plante se propage, aussi l'utilise-t-on souvent pour fixer les terrains menacés d'affaissement (digues, terre-pleins) et pour reboiser les sols stériles. Il colonise naturellement remblais, talus et terrains vagues. De son bois robuste et durable, on fait des piquets de vigne. Trituré, le bois produit de la teinture jaune.
Les grappes de fleurs blanches sont mellifères d'où le miel d'acacia. Riches en nectar, les fleurs de robinier peuvent être consommées en beignets ou en sirop.

Tell me if my translation makes sense from a technical point of view:

-The black locust shoots stolons (runners) that allows the plant to spread. That's why it's often used to prevent risks of landsliding (dikes, open areas) and to reforest barren lands.
It colonises naturally embankments and vacants lots. Its robust and sustainable timber makes good vine stakes. Crushed, it produces yellow dye.
Its white flowers' clusters are melliferous thus acacia honey. Rich in nectar, Locust flowers can be eaten in cakes or syrup.

Makes perfect sense francis.



Robinia is a [controlled] weed in Australia. Nasty spikes on it too.

But Francis (also my real name), I only said that the
bark looked similar. Had there been any of
acacia's leaves or locust's thorns in Alex's photos
then I would agree with your guess. My vote still
stands. Let's wait for Alex to choose...

Mature Populus Nigra with burrs showing remnants of witch's broom twigs on them.

Okay. Here is a picture of the foilage. I have went through all the books at the library. Internet search too. Still do not know the exact classification/species.

That's great that you could post the foliage!

Now we can identify that tree: it's a a white willow (Salix alba).

I was mistaken at first because of the similarity of the bark with the Robinia.

White willow leaves:


White willow bark:

Yes. Yes.

Thank you Francis.