I have worked with yellow poplar a number of times, in most cases it has been used as a secondary timber ie joist or rafters or as board stock.
In one case, poplar was cut along with mixed oak of the lot and sawn into mostly boxed heart 8 x 8, stacked together and air dried for about 9 months. The oak had minor checking, no wind and remained straight but the poplar had deep checking and troublesome wind and some bow. The checking presented difficulty in selecting joint location. I planed the wind out on two adjacent sides to form reference.
In another case, we used peeled poplar poles 8 in. butt for rafters in a open air structure, applied board sheathing and still experienced wind and seperation from the sheathing.
Another case we sawed and hewed poplar logs that was air dried with bark onthe log on bunks about 2 feet off the ground for about 3 years. The boxed heart 10 x 10 remained stable with moderate checking.
All cases were in unheated buildings.
My conclusion is when poplar dries very quickly dramatic checking and wind appears. End coating helps but evaporation from the side grain needs to be slowed. I expect green poplar beams in a heated building will be damaged by rapid drying.
From my observation of old buildings, poplar will weather rapidly if not well painted but poplar heart wood is more resistant to decay than red oak or red pine but poplar beams seem less stable than oak or pine.
Once I tried to convert poplar logs by riving into quarters results were poor due to winding cleave.
