The weight of the ash resulting from dry ashing spruce needles at 500° C can be predicted with good precision from the concentrations of calcium (Ca), potassium (K), magnesium (Mg), manganese (Mn), and silicon (Si) in the needles. The empirical factors associated with the individual elements are given. There is evidence that they can also be applied to leaves from other plants. The colour of the ash can be related to the Mn concentration in the needles. Dry ashing entails no losses for Ca, cobalt (Co), barium (Ba), K, rubidium (Rb), antimony (Sb), scandium (Sc), and zinc (Zn), whereas a very small loss was observed for cesium (Cs), and a very large for bromine (Br).