Generally, two values are measured in each growth ring: minimum density and maximum density (representing locations within the earlywood and latewood layers, respectively), although maximum density values seem to be a better climatic indicator than minimum density. (climateaudit.org)
Energy density values were taken from food composition tables and from Rolls and Barnett (40), whereas energy costs were based on supermarket prices in Seattle collected in the winter of 2003. (academic.oup.com)