Photodegradation accelerates coarse woody debris decomposition in
Photodegradation accelerates coarse woody debris decomposition in
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光降解加速了粗木质碎片的分解
作者：
吴春生;张志坚;王翰琨;李超;莫其峰;刘苑秋
太阳辐射增强（光降解）是全球环境变化的一个重要驱动力。粗木质残体（CWD）在森林碳（C）动态中起着关键作用，因为它占森林总C的相当大的比例。因此，了解光降解对CWD分解的影响和潜在机制对于评估森林碳储量至关重要。通过24个月的田间试验，研究了光降解对杉木、木荷和香樟CWD呼吸的影响。并测定了CWD温度和含水量变化对三种树种RCWD的影响。我们发现，光降解显着加速RCWD，其效果进一步放大，随着温度的升高。光降解处理提高了RCWD对CWD温度的敏感性。CWD温度可以解释不同树种和处理间RCWD变异的70%以上。研究结果表明，光降解对CWD分解和碳循环的积极影响可能会影响森林生态系统的碳循环。这些研究结果可能为未来全球变化背景下光降解和温度变化对森林生态系统生态地球化学循环的影响提供参考。
Enhanced solar radiation (induced photodegradation) is an important driver of global environmental change..Coarse woody debris (CWD) plays a key role in forest carbon (C) dynamics because it contains a sizeable proportion.of total forest C. Therefore, understanding the effects and underlying mechanisms of photodegradation.on CWD decomposition is critical for the assessment of C storage in forests..We conducted a field-based experiment to investigate the effects of photodegradation on the respiration of.CWD (RCWD) of Cunninghamia lanceolata (CL), Schima superba (SS), and Cinnamomum camphora (CC) over a 24-.month period in subtropical China. And we also determined the effects of changes in CWD temperature and.moisture content on RCWD of the three tree species. We found that photodegradation significantly accelerated.RCWD, with its effect further amplified by increasing temperature. The temperature sensitivities of RCWD to CWD.temperature as indicated by Q10 were increased by photodegradation treatments. The CWD temperature can.explain over 70% of the variation in RCWD among different tree species and treatments. Our results indicate that.the positive effect of photodegradation on CWD decomposition and C cycles could potentially impact C cycling in.forest ecosystems. These findings may provide insight on the effects of photodegradation and temperature.change on biogeochemical cycling of forest ecosystems under the future global change.