Forest foliage that comprises much of the forest floor litter has higher equilibrium moisture content, EMC, than woody components. The EMC's at 300 degrees K were found to increase as follows: grasses < fir-spruce needles < pine-cedar needles < aspen leaves-larch needles. Equations that express Gibbs free energy associated with moisture content were used to develop regression equations that predict the EMC's from temperature and relative humidity, RH, for temperatures between 278 degrees K (40 degrees F) and 322 degrees K (120 degrees F) and RH's between 10 and 90 percent.
United States Department of Agriculture, Forest Service, "Predicting Equilibrium Moisture Content of Some Foliar Forest Litter in the Northern Rocky Mountains" (1990). Forestry. Paper 56.