Hello,
There is a tradition of using poplar lumber. Here where I'm living farmers used it for flooring in hay lofts in their barns. Poplar is particularly wear resistant because of its fibrous composition, in a similar way wool is suitable for weaving. Also it was used as wagon bottoms. On an industrial scale, I think particularly in Belgium, it was also used for flooring in train cars. In France, timbers, either sawn or hewn, were used for building horse stalls because it is a relatively chemically neutral wood so doesn't react with fumes from the piss. Probably where you are living it has its own traditional uses - shingles is another one I've heard of.
So, these are some of the particular uses. But it was also used more generally in roof construction for houses, carpentry work and even furniture. Some of the things I've used it for are similar, flooring in the barn, siding also on the barn, I've planked walls with it in our house, made mouldings. I'm a furniture maker and I use it to make full scale models of furniture pieces and also as veneerer core for furniture components.
I wouldn't use it for everything ,for example, a floor in my house. And outside it should be, let's say, treated.
If you ever cut another one, as is always the case with lumber, it should be milled as soon after felling as possible. I've dealt with this more if you would like to click on that link below.
Greetings
Don Wagstaff