Tulip Poplar, Yellow Poplar or Tulip Tree (lirioendren tulipifera)wood is good stuff and has the greenish or purple heartwood that people have been talking about and that Robb White uses. This tree is related to Magnolias. it grows widely in the Eastern US tending to be the largest and tallest trees in the forest. they tend to have tall straight trunks, ideal for lumber. their lumber is listed by Peterson's tree guide as being used for furniture, boats, toys shingles amoung other things.

the Tulip tree is not related to the true Poplars. The Poplar family includes Aspens and Cottonwoods. Their wood is quite different from Tulip wood. It is light and soft which may be beter suited for lightweight kayak building. I'm sure some of the Western US builders may have access to Aspen and may have even used it in their boats.

--eric