Yuan Jie1, Cai Jing1,2, Hou Lin1,2, Zhang Shuoxin1,2*
1. College of Forestry, Northwest A&F University
2. Qinling National Forest Ecosystem Research Station

Storage and composition of fallen wood were investigated by sampling method of fixed area plot in a natural secondary Pinus tabulaeforims forest land at Huoditang forest region in the Qinling Mountains. The fallen wood mass on this land was averagely 8.25 t•hm-2, of which P. tabulaeformis and Toxicodendron vernicifluum accounted for 69.58% and 30.42%, respectively. Investigation on the storage of fallen wood according to an international classification showed that the storage of Ⅱ decay class was dominant, occupying 42.06% of the total, and the storage of Ⅴ decay class accounted for only 8%. The relationship of density and decomposition was simulated by monomial exponential attenuation model, the decomposition constant of P. tabulaeformis fallen wood was 0.039 93 (R2=0.981 78), while fallen wood of T. vernicifluum was 0.045 33 (R2=0.982 68). The monomial exponential attenuation model predicted that it took 17 and 75 years for P. tabulaeformis fallen wood to lose 50% and 95% of its mass. The monomial exponential attenuation model also estimated that it took 15 and 66 years for T. vernicifluum fallen wood to lose 50% and 95% of its mass.
Key words: Qinling Mountains; natural secondary Pinus tablaeformis forest; fallen wood; storage; decomposition; monomial
*Author for correspondence, sxzhang@nwsuaf.edu.cn