An Evaluation of Beta Attenuation for Estimating Aboveground Biomass in a Tallgrass Prairie

Abstract

The attenuation of beta particles by vegetation was evaluated as a nondestructive method for estimating aboveground biomass in tallgrass prairie in northeast Kansas. Regression equations using the sum of beta attenuation measurements for each of 5 height classes within the vegetation and mean midday leaf water potential as the independent variables were used to predict live and total biomass. Live and total biomass were better predicted on burned (r2=.91 and .88, respectively) than unburned sites (r2=.71$ and .70, respectively). Greater variability in the relationship between beta attenuation and biomass in unburned prairie was a result of the large and variable amount of dead biomass on unburned sites. Dead biomass was poorly predicted by beta attenuation (r2=.24-.49). Beta attenuation predicted biomass in burned tallgrass prairie within +/- 5% of harvest values until late season vegetative senescence. In unburned prairie, predictions were poorer, but the technique could still be useful if the required accuracy need be only +/- 25%.