Juglans cinerea (I hope) Juglans nigra at the end of winter

Juglans cinerea, known in English as "butternut" or "white walnut", and in French as noyer cendré, noyer blanc, or noyer à beurre, is a deciduous tree native to eastern North America. Currently butternut is endangered in Canada, because of a canker disease which has killed up to 90% of butternut trees (which were not common to start with).

This tree, and its twin (not shown), caused a bit of consternation as we attempted to identify them. My landlord's son was convinced they were a weed; he was probably confusing it with Ailanthus altissima, an invasive species here in southern Ontario. Luckily the people at Dave's Garden were able to confirm that this is not Ailanthus, though there was no agreement on what it is. Here's a close up of the fuzzy buds, for what it's worth. And here's the bark, which doesn't seem right for butternut but doesn't seem right for the other leading possibility (black walnut, Juglans nigra) either. I haven't seen flowers or nuts on this tree, but maybe it will produce some this year and I'll be able to ID it.

Update March 29

After I posted a photo of the chambered pith in a twig from this tree, plant identification guru Resin at Dave's Garden confirmed that it is Juglans nigra (black walnut), not the endangered butternut. It's still a nice native tree and I'm sure the squirrels will be happy when it produces nuts!