木质物残体（Woody Debris，WD）是森林生态系统中重要的结构性和功能性组分。但是，极少学者认识到全球木质物残体分解释放的CO2总量（约7.7—9.5 Pg C year-1）与化石燃料燃烧释放的CO2总量（约9.6 Pg C year-1）大体相当。
为了探讨木质物残体分解作用的变化规律及其影响因子，版纳植物园土壤生态研究组硕士研究生刘伟杰在导师Douglas Schaefer博士的指导下，针对哀牢山地区的三个原生优势树种的木质物残体开展了相关实验。
研究结果显示：同组（相同树种、相同分解等级）的不同木质物残体个体之间的呼吸速率差异很大，而木质物残体的温度和含水量的二元呼吸模型的R2值仅为0.25—0.57。这说明温度和含水量是影响木质物残体分解的重要因子，但是仍存在其他不确定因素导致木质物残体分解速率的差异。木质物残体分解者之间普遍是相互抑制的，而且对人工接种的真菌群落而言，具有较高物种多样性的木质物残体分解反而较慢，但是仍需深入探讨天然微生物群落与木质物残体分解作用之间关系，这将对评估木质物残体在全球碳循环过程中的作用有重要意义。
相关研究结果以What controls the variability of wood-decay rates？为题发表在Forest Ecology and Management上。本研究得到了国际APN基金和国家自然科学基金项目的支持。（生物谷Bioon.com）
生物谷推荐的英文摘要
Forest Ecology and Management doi.org/10.1016/j.foreco.2013.09.013
What controls the variability of wood-decay rates？
Weijie Liua， Douglas Schaefera， Lu Qiaoa， Xianbin Liua
Decaying wood provides essential habitats for forest biota， and its CO2 return to the atmosphere is comparable to that from fossil-fuel combustion. Decomposition rates for wood debris (WD) from three tree species were measured by CO2 release in a subtropical forest over two years. Wood temperature and moisture were measured along with CO2， and each WD piece (n = 320) was characterized by its initial weight， density， volume， surface area， and decay class. For individual pieces of WD in each wood-species and decay-class group， predictions of release rates based on temperature and moisture together had R2 values ranging from 0.25 to 0.57， predictions based on moisture alone had R2 values ranging from 0.16 to 0.35， and R2 values from 0.07 to 0.35 were seen in temperature-only predictions. Wood density and surface area were negatively related to CO2 release rates (R2 = 0.10 and 0.04 respectively， over all groups). We also used daily meteorological measurements to predict WD temperature and moisture. Average air temperatures predicted WD temperatures with R2 values above 0.7 over 35 days， but total rainfall was a very weak predictor of WD moisture over any interval. We used temperature – decay relationships to estimate annual total CO2 release from WD groups， and found that their average exponential decomposition rate (K) was 0.09 year？1. Based on density loss， most WD in the studied forest would be in the late stage of decay， in contrast to some previous studies. Our results support previous studies on the importance of environmental factors in determining WD decomposition， but with only half of the variation explained， we are challenged to explain the rest. Aggressive interactions are common among WD decomposers， and previous work with simplified microbial communities suggests that high diversity leads to slower decomposition. Uncertain predictions for WD decomposition rates， and their global C- cycle implications， will persist until interactions of WD microbial communities are better understood.
