Columbia subject headings:
Biomass energy--Environmental aspects--United States.
Energy crops industry--United States.
Energy crops--Environmental aspects--United States.
Harvard subject headings:
Biomass energy--Environmental aspects--United States.
Biomass energy--United States
Energy crops industry--United States.
Energy crops--Environmental aspects--United States.
Energy crops--United States.
Princeton subject headings:
Biomass energy--Environmental aspects--United States.
Energy crops industry--United States.
Energy crops--Environmental aspects--United States.