Abstract:Coarse woody debris (CWD) plays important structural and biogeochemical roles in Tianshan Picea schrenkiana forest ecosystem processes. Explaining its storage characteristics is the basis for studying CWD. However, on a large-scale no studies have yet been reported. Based on the combination of field investigation, laboratory test and data analysis, study objectives of this report were to examine storage estimate by composition, diameter and decay class distributions and its effect factors in P.schrenkiana forest of Tianshan Mountains. Results indicate that:(1) A substantial number(936) of CWD(≥ 10 cm diameter)exists in 8 hm2 P. schrenkiana forest dynamics plot. Density, volume and storage of CWD in this plot averaged 117 N/hm2,15.13 m3/hm2 and 4.52 t/hm2. Logs were the main contributor and accounted for 52.21% of the total CWD storage, while the percentage of snags and stumps were 20.58% and 27.21%. (2) We found that CWD quantity in P. schrenkiana forest by diameter class was followed the inverse J-shaped. The diameter distribution of this population is highly skewed towards smaller-sized (﹤30 cm dia.) CWD, which accounted for 83% of total CWD quantity. (3) In the sample plot, snags and logs are mainly at the mid-low decomposition level, while stumps are concentrated at decay class Ⅲ, IV, and V. The distribution of total CWD by decay class is skewed toward decay class Ⅱ and Ⅲ. Overall, the current decay class distribution of CWD in P. schrenkiana forest appears to follow a natural progression of CWD decay. (4) Our results also showed that the CWD diameter in the plot has a certain influence on the distribution of decay class. With the increase of the diameter, the degree of CWD decomposition continues to increase. (5) Stand density, canopy density and elevation are the main factors affecting the storage characteristics of CWD in P. schrenkiana forest of Tianshan Mountains. This study can provide a scientific evidence for the sustainable development and management of P. schrenkiana forest.