Russ,
From what I've read, poplar is a member of the willow family which includes cotton woods and aspens. It's a fast growing pioneer tree which along with birch colonizes cut over or abandoned farms in upland areas and reaches maturity in about 40 years. It seems to vary in color from creme to pinkish. While classified as a hardwood it is similar to white pine in hardness and weight. It also has similar resistance to rot as pine. Poplar has a bad reputation for rot because if left with its bark on it will rot very quickly. I think that's because the bark holds the moisture in the log. Ash and birch have the same problem. Maple which is not recommend for boat building seems to last a lot longer in the log. Go figure.

I agree that it is easy to work and is stable. It also takes paint well. tradition furniture makers use it for those parts of solid wood furniture that ordinarily are not visable, such as drawer sides and bottoms, dust and backing panels and cross banding under more expensive veneers. I plan to try it on my next stripper. The only disadvantages I see are that it's a little heavier than cedar and has little to offer in terms of gain or pattern. I'm curious what could be done with analine dyes given it's love of paint.

Lastly, between me and my neighbors we've got about 50 acres with mature poplars being wind thrown or snap their crowns all the time. So I get offered a lot of "free" trees. These trees produce clear bolts upwards of 20' and average about 12" in diameter at chest height. A log like that'll make 6-8 kayaks. Not accounting for the cost of the mill, it costs less tham 15 cents a board foot to mill clean or barked poplar (dirty logs can quickly dull a $25 blade which runs $6 to sharpen) into 1" boards compared to $4 or so per bdft. for western red cedar here on the right coast. So the price is right.

As a result, I use for everything from furniture to structural timbers. So why not a boat? Hope this helps.
George C.