I've never tapped trees, but there's one maple we planted in our back yard. The thing is covered in sap. I did taste a bit (don't call me a treelicker), and it was awfully sweet tasting stuff. I doubt I'd get much from a single tree, but I could see myself getting into it... heck, if I live long enough to retire, I'll be one of those eccentrics out on a goat farm, brewing beer, making cheese, tapping trees, and keeping bees.