Bud, Is poplar a traditional wood for dugouts? I know that it is not recommended for most exterior applications due to it's lack of rot resistance. The following is from a marine lumber distrubutor:
"Poplar
This wood is a pleasure to work with. It is pale cream to green in colour. The green fades to a very nice shade of light brown. It is not suitable for constructing hulls and decks in boat building, although it can be used internally for joinery and items such as panel doors and drawers. This is also a good domestic material for furniture, and solid wood floors."
However, if you have the logs....
Mike