Acacias are evergreen, nitrogen-fixing plants ranging in form from ground covers to tall trees. There are more than 1200 species worldwide. There are many roles for acacias in permaculture design such as increasing soil fertility through nitrogen fixation, rehabilitation of degraded soils and in reforestation.

Which trees are nitrogen fixers?

Black Locust, Mimosa, Alder, Redbud, Autumn Olive, Kentucky Coffee Tree, Golden Chain Tree, Acacia, Mesquite and others are examples of trees that support nitrogen in soil with the help of bacteria. These NFTs pull the element out of the atmosphere and build a storehouse of the gas through their nodule root formation.

What enzymes fix nitrogen?

Nitrogen fixation is carried out by the enzyme nitrogenase, which are found in microbes.