Is a tulip tree considered a unyielding wood? ...
Answers: Yes, hardwoods are basically angiosperms (broadleaved, mostly deciduous trees) versus softwoods or conifers (cone position trees).
Yes... and no. If you are referring to its wood properties, than No. Tulip trees, and poplar (aspen), have enormously soft wood (for being labeled a "frozen wood"). Many pines (which are soft woods) have harder wood than tulip trees. Those titles don't really engineer any sense. So if your looking for something like hardwood flooring, don't use tulip poplar.