| 摘要: |
| 【目的】加深对倒木呼吸年变化过程和机制的认识，获得准确的倒木呼吸年通量，为森林碳循环研究提供更加准确的数据。【方法】在秦岭火地塘林区主要森林类型油松林和锐齿栎林内各设置100 m×100 m的固定样地6块，根据相关标准将样地内倒木划分为5个腐烂等级，在样地内选择直径在(25±5) cm、腐烂等级不同的油松和锐齿栎倒木各3株，通过红外气体分析法原位测定倒木呼吸速率，同时测定倒木温度、倒木含水量和林内10 cm深处土壤温度，并计算油松林和锐齿栎林的倒木呼吸年通量，通过分析油松和锐齿栎倒木呼吸速率年变化、倒木呼吸速率与倒木温度和含水量的关系，比较油松林和锐齿栎林倒木呼吸年通量的差异。【结果】（1）油松和锐齿栎倒木各月呼吸速率均变化显著（P＜0.05），8月份最高，分别为4.78和6.45 μmol/(m2·s)，2月份最低，分别为0.10和0.06 μmol/(m2·s)；倒木呼吸速率与倒木温度、倒木含水量和倒木腐烂等级均呈显著正相关（P＜0.05），倒木温度解释了67%以上的倒木呼吸变化；锐齿栎（(1.72±1.64) μmol/(m2·s)）与油松（(1.57±1.45) μmol/(m2·s)）间的年均倒木呼吸速率无显著性差异（P＞0.05）。（2）油松林（(66.04±8.25) g/(m2·a)）和锐齿栎林（(73.32±8.68) g/(m2·a)）的倒木呼吸年通量无显著性差异（P＞0.05），但油松林的倒木表面积（(1 008.83±89.84) m2）显著高于锐齿栎林（(844.56±64.58) m2，P＜0.05）。【结论】油松和锐齿栎倒木呼吸的年变化均呈现出基本一致的单峰曲线格局，主要受倒木温度的驱动，同时倒木含水量和腐烂等级也对倒木呼吸有显著影响，但树种对倒木呼吸的影响较小。 |
| 关键词: 倒木温度 倒木含水量 倒木呼吸 倒木腐烂等级 |
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| 基金项目:国家自然科学基金项目“秦岭倒木呼吸通量及其影响机制的研究”（31800372）；中央高校基本科研业务费专项“倒木分解过程中的微生物群落特征研究”（2452018076） |
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| Respiration flux of downed log in Pinus tabulaeformis and Quercus aliena var.acuteserrata forests at Huoditang forest region in the Qinling Mountains |
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YUAN Jie,ZHAO Yan,ZHAO Yunpeng,et al
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| Abstract: |
| 【Objective】This study investigated the driving mechanism and process of carbon cycle in forest ecosystem and obtained accurate respiration flux of downed log to provide more accurate data for carbon cycle studies in forest ecosystems.【Method】Six repeated plots with an area of 100 m×100 m were established in P. tabulaeformis and Q. aliena var. acuteserrata forests. Each log was assigned to one of five decay classes based on internal and external tissue characteristics.A total of 30 logs (3 replicate logs×5 decay classes×2 tree species) with diameters of (25±5) cm were selected.The log respiration rate was measured in situ by infrared gas analysis to accurately reveal the annual variations.Additionally,log temperature,soil temperature at 10 cm depth,and log water content were measured simultaneously.The relationships between log respiration rate with log temperature and log water content were analyzed,and the annual log respiration fluxes in the P. tabulaeformis and Q. aliena var. acuteserrata forests were compared.【Result】(1) Significant monthly variation was observed in the log respiration of P. tabulaeformis and Q. aliena var.acuteserrata (P<0.05) with the highest of 4.78 and 6.45 μmol/(m2·s) in August and the lowest 0.10 and 0.06 μmol/(m2·s) in February.The log temperature,water content,and decay classes were positively correlated with log respiration (P<0.05).The variation in log temperature explained above 67% of the variation in log respiration.There was no significant difference in the annual mean log respiration between P. tabulaeformis ((1.57±1.45) μmol/(m2·s)) and Q. aliena var. acuteserrata ((1.72±1.64) μmol/(m2·s),P>0.05). (2) The total annual log respiration flux did not differ significantly between the P. tabulaeformis forest ((66.04±8.25) g/(m2·a)) and Q. aliena var. acuteserrata forest ((73.32±8.68) g/(m2·a),P>0.05),but the total log surface area was significantly higher in the P. tabulaeformis forest ((1 008.83±89.84) m2) than in the Q. aliena var. acuteserrata forest ((844.56±64.58) m2,P<0.05).【Conclusion】The log respiration displayed significant monthly variation mainly driven by log temperature.Log water content and decay classes also had significantly effect on log respiration,but tree species had no significant effect. |
| Key words: log temperature log water content log respiration log decay classes |
