Nitrogen fixing trees and legumes

We are currently researching nitrogen fixing trees for arid regions.
These trees work in a symbiotic relationship with various fungi such as mychorrozium and or rhizobium. In a simplified way, one can say that these trees absorb nitrogen from the air and transport it to their roots while the fungi and bacteria does the rest of the work at the root nodules.

We are looking for a variety of these trees that are capable of producing different resources such as ; fodder, mulch, food, flowers (for bees and other beneficial insects), shade and shelter from the winds. An important aspect that most of these trees must have, is the ability to withstand salty winds.
Since we are working in an arid and windy area, our challenge is to combine the right trees and incorporate them in the permaculture design to re-generate food forests, while protecting nature and revitalise the soil and its microbacteria. By doing all this, one will start to notice that nature starts to take its circular integral form again in the sence that systems support each other and thus there will be less need for human intervention as time succeeds. The right trees shall also function in order to attract the right balance of insects and other fauna in order to achieve a natural pest control system and therefore avoid any use of artificial insecticides and fertilizers.
This is the way forward if we truly want to see a future in permanent agriculture that can afford food security, bio-diversity and edible landscapes.

If you are interested in volunteering on the project or getting to know more, please email Peppi on peppizen@yahoo.co.uk.