Two things were disappointing.
The recent sun has caused the plants to flourish. OK, this is good, but most of the plants are sting nettles. It was rather painful making my way to the fallen trees. Afterwards I found a dock leaf which helped ease the sting. Turns out that a tincture made with dock leaves eases menopause problems. Might need some more.
The other disappointment was that the leaves don't seem to smell anymore. When I plucked that twig the scent was quite strong - if you poked your nose into the leaves. I tested it by poking the leaves into the nose of three people I met while carrying the twig back to my car. They all smelled it. It was not an aromatic hallucination!
But when I sniffed this time, only one twig, with a sort of catkin thing, offered any scent and that was slight.
If it is a Black Poplar, then these catkins should be red...
Balsam Poplars might have green catkins....
The leaves all seem shiny and rather sticky or waxy now - though still very fine and smooth.
The standing trees, although bearing few branches, all of which point upwards, are ahead of the game in terms of coming out in leaf. Only hawthorns are so far advanced.
Looking at the shape of them, I wondered if they are Lombardy Poplars but well... I am clearly not great at tree IDs. Apparently, one hybrid of the Lombardy and Wild Black does have a stronger balsam smell than other poplars, except the Balsam Poplar. This would make sense as one defining factor of the Wild Blacks is that they tend to have a short trunk with many bosses (knobbles, I think), while these are very tall and slim. Also because the hybrid, Plantieres Poplar, 'Plantierensis', is apparently always worth looking out for though quite common in some areas.
Maybe they don't like being so close together or maybe they are diseased. apparently the Lombardy is prone to many diseases.
Still, whatever is going on and whatever they are, the fallen trees are still alive.
And, in my little vase at home, those leaves still bear that lovely scent. More delicate, but still there.
I took a quick look here - https://www.woodlandtrust.org.uk/trees-woods-and-wildlife/british-trees/a-z-of-british-trees/black-poplar/?gclsrc=aw.ds
I wonder if your picture from your tree is from a female tree (yellow green catkins). Male and female trees are separate.
Oh I see the Lombardy has finely toothed leaf margins. You might check that again. Both Black and Lombardy are heart-shaped.
Oh look at this - http://gallery.nen.gov.uk/asset62026_15506-.html
Above link talks about "bosses on the bark" ?????
Oh - bosses - https://www.discoverwildlife.com/plant-facts/plant-id/how-to-identify-a-tree-from-its-bark/
And here's a close up of Lombardy leaf -https://www.stagrallergymap.com/trees/lombardys-poplar
Margins teeth about the same? As you say may be a hybrid.