It is low value veneer - mostly used for the inside layers of plywood. Sometimes used for face material in more "utilitarian" uses. Frankly tall straight tulip-poplar are pretty common.
You say they are in the back yard...how are loggers going to get to those? Are you OK if they just drop them, cut the top off and drag them out? Otherwise, a tree removal company is going to cost more than the logs are worth...but you may be able to cover a small portion of their cost by selling logs.