Energy flow and nutrient recycling are two important areas of ecological investigation. The purpose of these experiments is to assess the growth rate and net primary production of heather, Calluna vulgaris L., as a basis for estimating energy flow and nutrient uptake. The experiments take various measurements of specimens from different locations (though within the same area), at different phases of the plant's life cycle and subject to such differences as grazing and rotational burning. The measurements demonstrate the relationship between mean standing-crop biomass and age, the average annual increment in above ground standing-crop biomass, the effect of the formation of a closed canopy on the production of green material, and the efficiency of energy fixation by heather during the growing season. (15 minutes)