Aboveground annual net primary production (ANPP) has been measured on the LTER main site since 1990 and on the successional and forested sites since 1993. ANPP is measured at peak biomass for a given treatment. In some systems with multiple harvests or complex communities that have peaks occurring at different times of the year, measurements are taken at multiple times per year. Additional ANPP measurements are made where appropriate using leaf litter traps, estimates of diameter from tree basal diameter and for the poplar treatment occasional destructive harvests. See the ANPP protocol for descriptions of the sampling and measurement methods for each of the treatments.
original data source http://lter.kbs.msu.edu/datasets/22