Inconsistent responses of soil respiration and its components to thinning intensity in a Pinus tabuliformis plantation in northern China
Inconsistent responses of soil respiration and its components to thinning intensity in a Pinus tabuliformis plantation in northern China
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DOI：
10.1016/j.agrformet.2018.11.034
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发表时间：
2019-02
影响因子：
6.2
通讯作者：
Bo Zhao;Jing Cao;Yan-Yan Geng-Yan;Xiu-hai Zhao;K. von Gadow
中科院分区：
文献类型：
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作者：
Bo Zhao;Jing Cao;Yan-Yan Geng-Yan;Xiu-hai Zhao;K. von Gadow
了解土壤呼吸（Rs）对间伐的响应是评价种植园林生态系统碳循环的管理措施的重要内容。然而，如何Rs及其组件（自养，Ra和异养呼吸，Rh）随间伐强度和潜在的机制还没有很好地理解。在本研究中，我们监测Rs，Ra和Rh在5个生长季节使用挖沟法在油松人工林进行4个间伐处理（不间伐，CK;轻间伐，LT;中度间伐，MT和重度间伐，HT）。平均而言，LT和MT显着增加Rs分别为13%和17%，与CK相比。这些增量的Rs归因于增强Ra在LT和MT地块，因为轻，中度间伐促进根系生长和生产力（更高的细根生物量）。然而，HT并没有导致Ra的进一步增加，这表明剩余的树木和林下植物的活动增加并没有补偿减少的光合作用和大量的树木砍伐的呼吸树根。与Ra相反，Rh的变化与间伐无关，部分原因是由于间伐和对照地块之间的稳定森林地面质量（非生物有机物质，如凋落物和细木质残体）和微生物生物量碳含量（MBC）。Ra和Rh的温度灵敏度（Q_（10））分别为1.40 ~ 3.07和2.34-3.42。Ra的Q10值在MT中最高，而Rh的Q10值在LT中最高。土壤湿度与Rh显著相关，但对Ra的预测效果较差。我们的研究结果表明，Ra和Rh响应间伐强度相互独立。在评估森林管理对种植园林固碳潜力的影响时，管理强度和植物介导的生物过程特别重要。
Understanding the responses of soil respiration (Rs) to thinning is essential to evaluate the effects of management practices on carbon cycling in plantation forest ecosystems. However, how Rs and its components (autotrophic, Ra and heterotrophic respiration, Rh) vary with thinning intensity and the underlying mechanisms are not well understood. In the present study we monitored Rs, Ra and Rh over five growing seasons using a trenching method in aPinus tabuliformisplantation subjected to four thinning treatments (no thinning, CK; light thinning, LT; moderate thinning, MT and heavy thinning, HT). On average, LT and MT significantly increased Rs by 13% and 17%, respectively, compared with the CK. These increments of Rs were ascribed to the enhanced Ra in LT and MT plots, because light and moderate thinning promoted root growth and productivity (higher fine root biomass). However, HT did not result in a further increase in Ra, suggesting that increases in the activity of remaining trees and understory plants did not compensate for the reduced photosynthesis and the amount of respiring tree roots by extensive tree-cut. In contrast to Ra, variation in Rh was unrelated to thinning, partly due to the stable forest floor mass (non-living organic materials such as litter and fine woody debris) and microbial biomass carbon content (MBC) between thinned and control plots. The temperature sensitivity (Q10) of Ra and Rh ranged from 1.40 to 3.07 and 2.34–3.42, respectively. The highest Q10of Ra was observed in MT while that of Rh occurred in LT. Soil moisture was significantly correlated with Rh but a poor predictor for Ra. Our findings demonstrated that Ra and Rh responded to thinning intensity independently of each other. The intensity of management and plant-mediated biological processes are of particular importance in evaluating the impacts of forest management on C sequestration potential in plantation forests.