Originally Posted by yewberry
Because it seems unlikely anyone else will mention it, I'm tapping my bigleaf maple trees and freezing the sap for steam-boiling later this winter. You can tap maples, alders, birches, and I've heard tell about tapping willows and cottonwood, too. The bigleaf sap is a little lower in saccharides than sugar maples, but it makes dandy, delicious syrup.
That is very interesting. I had no idea it was possible, but I found an old PDF of a study done by the US Forest Service evaluating the hobby and commercial prospects of maple sap harvesting, which they deemed promising.