That sucks. I'm not sure I'm much help for the why though. Any recent wind storms, new pavement laid down or weeks with 100 degree days and no water? Otherwise it looks reasonable.

Looks like a Populus species. They can be fragile. Maybe get it inspected by a qualified person?

hire a certified arborist and pay for a local onsite inspection ....

every guy with a chainsaw is not an arborist..

https://duckduckgo.com/?t=ftsa&q=isa+arborist&ia=web

large branches falling is usually related to storm winds.. or ice/snow in winter storms...

but smaller branch litter can be a squirrel making a nest.. but that is usually in much larger trees..

ken

Poplars don't have strong wood. Looks like a windstorm went thru, or maybe squirrels or some other critters like to chew on poplar wood.....

I would suspect a strong downdraft from a recent storm

I have a huge cottonwood in my yard. Thats what mine does after any wind event. If it were for the fact that the eagles like to perch in it and catch fish I’d cut it down.