The decomposition of coarse woody debris (CWD) affects the energy flow and nutrient cycling in forest ecosystems. Previous studies on CWD have focused on the input, decomposition, reserve dynamics, and CWD functions, but coarse woody debris decomposition is complex and the results from different regions vary considerably. It is not clear which factors affect decay rate (k), especially at different decomposition stages. In this study, a single-exponential decay model was used to analyze the characteristics of CWD decomposition in Larix gmelinii forests over the 33 years following a fire in the Greater Khingan Mountains. The results show that the decay rate of coarse woody debris was positively correlated to decay class. The average decomposition rate was 0.019, and 41 years and 176 years are needed for a 50% and 95% mass loss, respectively. CWD nutrient content, density, and water content could explain the variance in the decay rate (~ 42%) of the decay factors such as amount of leaching, degree of fragmentation, respiration of the debris, and biotransformation, and varied significantly between different decay classes. Using the space–time substitution method, this study arranged the coarse woody debris of different mortality times to form a 33 year chronosequence which revealed the decomposition process. It was concluded that the decay rate was mainly explained by structural component of the debris and its nitrogen and water contents. This paper quantifies the indicators affecting CWD decay to explain the decomposition process.

粗木屑的分解会影响森林生态系统中的能量流和养分循环。以前对CWD的研究集中在输入，分解，储量动力学和CWD函数上，但是粗大的木屑分解非常复杂，不同地区的结果差异很大。尚不清楚哪些因素会影响衰减率（k），尤其是在不同的分解阶段。在这项研究中，使用单指数衰减模型来分析落叶松CWD分解的特征。大兴安岭大火过后33年中的森林。结果表明，粗木屑的衰减速率与衰减等级呈正相关。平均分解速率为0.019，而质量损失分别为50％和95％则需要41年和176年。CWD的养分含量，密度和水分含量可以解释腐烂因子的腐烂率（〜42％）的变化，例如浸出量，破碎程度，碎片呼吸和生物转化，并且在不同腐烂之间差异显着类。本研究使用时空替代方法，将不同死亡率的粗木屑排列成33年的时间序列，揭示了分解过程。可以得出结论，腐烂率主要由碎片的结构成分及其含氮和含水量解释。本文对影响CWD衰减的指标进行了量化，以解释分解过程。