抚育间伐对云南松非结构性碳和化学计量特征的影响

Effects of tending and thinning on non-structural carbon and stoichiometric characteristics of Pinus yunnanensis

【目的】探究抚育间伐对云南松各个器官非结构性碳(NSC),以及碳(C)、氮(N)、磷(P)化学计量学特征的影响机制。【方法】以云南省永仁县国有林场白马河林区云南松中龄林为研究对象,设置间伐(间伐强度为35.4%)与对照样地,分析抚育间伐对云南松非结构性碳和化学计量特征的影响。【结果】(1)抚育间伐显著影响云南松针叶和枝的NSC含量(P<0.01),对根NSC含量则无显著影响。抚育后枝NSC含量增长9.30%,而针叶NSC含量减少3.57%。(2)抚育间伐对云南松枝C含量、针叶和干P含量有显著影响(P<0.05),对针叶N含量有极显著影响(P<0.01),但对根的C、N、P含量没有显著影响。抚育后云南松枝中C含量增加12.93%;针叶中N含量增长18.04%;叶和干中P含量分别降低了27.78%、55.56%。(3)云南松NSC、CNP化学计量学特征在各个器官之间表现出显著差异(P<0.05)。相关性分析表明:针叶和根P含量与可溶性糖含量呈显著正相关(P<0.05),而叶中C含量则和可溶性糖含量显著负相关(P<0.05)。【结论】抚育间伐能促进云南松干、枝和根NSC含量以及各器官C含量的积累,降低叶NSC和各器官P含量,改变C、N、P在各器官中的分布格局;该地区云南松人工林生长在一定程度上受N限制,适当配施N肥将促进林分质量的提高。

[Objective]Our objective was to explore the mechanism of the effects of thinning on nonstructural carbon(NSC),carbon(C),nitrogen(N)and phosphorus(P)stoichiometry of Pinus yunnanensis.[Method]The middle-aged P.yunnanensis forests were chosen in the Baima River forest area of Yongren County,Yunnan Province of southwestern China,and two experimental sample plots of thinning(thinning intensity of 35.4%)and control were set up to analyze the effects of thinning on NSC and CNP stoichiometric characteristics of P.yunnanensis forests.[Result](1)Tending thinning significantly affected the NSC content of needles and branches of P.yunnanensis(P<0.01),whereas no significant difference on roots was observed.In addition,the NSC content of branch increased by 9.30%,while the NSC content in needles decreased by 3.57%.(2)Thinning had a significant effect on C content of P.yunnanensis branch,P content in needles and stems(P<0.05),and a highly significant effect on N content in needles(P<0.01),however,no significant effect was observed on C,N and P content in roots.After thinning,the C content of P.yunnanensis branch increased by 12.93%;the N content in needles increased by 18.04%,and the P content in needles and stems decreased by 27.78%and 55.56%,respectively.(3)The NSC,CNP stoichiometric characteristics showed significant differences among P.yunnanensis organs(P<0.05).Correlation analysis showed that the P content in needles and roots was significantly positively correlated with soluble sugar content(P<0.05),while C content in needles was significantly negatively correlated with soluble sugar content(P<0.05).[Conclusion]Thinning promots the accumulation of NSC content in stem,branch and root and C content in each organ,whereas needle NSC and P content decreased in each organ,furthermore,distribution pattern of C,N and P in each organ was affected;the growth of P.yunnanensis plantation in this area was limited by N to some extent,and appropriate application of N fertilizer will promote the improvement of stand quality.