Addressing both the 'Search' feature as well as the more general discussion about poplars, I found this:

https://www.houzz.com/discussions/trees/query/poplar/nqrw

Personally, I would not consider poplars to be very good trees for a typical suburban garden. And that is because they, like much of the Populus genus, tend to produce a lot of root suckers and form colonies. The largest single organism on the planet is a 160 acre cluster of quaking aspens that have been established to all be one single plant. Poplars will do the same in the middle of your lawn.

Ack! Maybe these are suckers, not seedlings like I assumed. I don't see them popping up anywhere else, though. I'm more concerned about them being weak trees prone to breakage. Far enough away from the house so they won't do any damage but I don't want cr*ppy trees, either, just for the sake of having free trees.

I'm keeping my eye on that one by the barn -- it will crash right though the roof of the barn if a storm takes it down. If tree remove weren't so expensive I would have had it done by now (it's much too large for DH to do himself).

What kind of poplar? I have several tulip poplars in my yard. I find them very nice trees. In the spring they have pretty yellow flowers. They don't seem to loos a lot of limbs, and the leaf production is about the same as the average tree.

There is one problem with them. They grow tall. I don't know how old they are as they originally were on a wooded lot, and they branches were near the top. The cut the small trees and undergrowth to build the house. That was about 16 years ago. During the 12 years we have had the house they have grown lower branches and now are a good source of shade.

The reason I mention that they were tall, is they would not be a good tree on in crowed addition with small lots. My poplars are taller that my two story house, and as the tree is growing lower branches, that on a small lot would be in your bedroom.

No, not tulip trees (aka tulip poplars). I have a couple of those already, they are wonderful trees. I'm talking about the scrubby poplars, I think (think...) they're Lombardy poplars.

Poplars are notorious for growing fast, and dying young. So they are popular for quick windbreaks. I'm not sure I see the point in keeping the ones you have as lawn trees, but then my volunteer weed trees tend to be hickories or red maples.

Cottonwoods don't typically sucker, but they get big very fast and branches break. Not a good choice for yards.

Some pics:

This is the nice one:

Leaves:

One of the saplings (yes, it know it's a weed sh*tshow, no need to point that out...):

Damaged one I'm concerned about:

Last one looks like maybe some type of stem/branch canker, but can't be sure. But it looks like a common occurrence for poplars in my area.

I have a poplar wood, mxk3. I knew sod all about them before we bought the land but have come to love them. They do grow fast (mine are mostly hybrids, grown for matchwood) but I have since added both black and white poplars. One of the most notable things (of having a poplar plantation) was the height of the canopy and the possibility for light underneath. I have grass and wildflowers, as well as a hazel, elder and hawthorn understorey. White poplar is beautiful in the landscape, especially with guelder roses and willows, while black poplar, once a common UK tree, is now ridiculously rare (because seeds have the shortest viability of any tree seeds and have to be grown from cuttings.