Leguminous tree seed as fertilizer or fuel.

I was thinking of  alternatives to oil based fertilizer, things like alfalfa meal, when it struck me that we could gather this resource from the overstory.
I'm thinking black locust in particular, since that's what grows around me.
Ground up in a ball mill, these seeds should provide a lot of nitrogen.

You could also process them to extract the bare seeds from the dry pods and use the seeds as fuel in a pellet burning stove.