Productivity

• The gross primary production (GPP) is the total quantity of the chemical energy store in plant biomass, in a given area or volume (in a given time).
• The net primary productivity (NPP) is the chemical energy store that remains after 20-50% of the GPP has been used up in respiration.
• The equation for net primary production (NPP) is : NPP = gross primary production (GPP) - respiratory losses (R).