i am looking for trees that has these traits nitrogen fixing, drought tolerant, produces fruit that is edible, can grow in zone 3 and 9.also if you know of any good website that sells them for a good price and for good quality please let me know.
The link to a discussion, given by Jack, above, has lots of people's suggestions for nitrogen fixers for different climates, usages, winter hardiness zones, etc.
Works at a residential alternative high school in the Himalayas SECMOL.org . "Back home" is Cape Cod, E Coast USA.
Then YOU must do the pig's work! Read this tiny ad. READ IT!
Binge on 17 Seasons of Permaculture Design Monkeys!