My Dad and I are currently building a kayak (and eventually a second) mostly out of redwood siding from a house he is remodeling. Since it is recycled we can build our boats out of beautiful old growth redwood without contributing to deforestation. I'd encourage everyone to try to find old redwood.

On a side note, I just had an idea, If they ever legalize hemp would a hemp fiber/ epoxy resin kayak be feasable, I suppose the main problem would be the mold required. If it worked it would be cheaper than fiberglass.