Abstract:With the litterbag method, the decomposition of twigs of oak (Quercus liaotungensis), a dominant tree species in warm temperate deciduous broad-leaved forests, had been investigated in five years consecutively. Changes of concentrations and the remaining percentage of five nutrient elements, namely C, N, K, P, Na, were determined. It was found that changes of nutrient concentrations and remaining percentages differed among those five nutrients throughout the five-year decomposition. Based on the Olson exponential equation, K had the highest decomposition constant. As for the change pattern of nutrient concentration, K decreased continually. C had almost the same tendency. N had the tendency of increase. P and Na increased during the first stage of the decomposition, and then decreased.