The biological decomposition coefficient (BDC) of N, P, and K in dead roots and fallen needles appeared the increasing trends with forest age, and was 0.7-1.5, 1.1-1.7, 1.0-3.5, and 0.9-1.3,1.1-1.7,1.0-1.3, respectively.

• a-~1。 凋落物层中的N、P、K贮量随林龄增大呈先增加后减少的趋势；全氮、全钾、全磷贮量的变化范围分别为142.；76-534