以闽北地区常见人工林树种壳菜果（Mytilaria laosensis Lecomte）、木荷（Schima superba Gardner et Champ.）、黧蒴锥〔Castanopsis fissa （Champ. ex Benth.）Rehder et E. H. Wilson〕、南酸枣〔Choerospondias axillaris（Roxb.）B. L. Burtt et A. W. Hill〕、杉木〔Cunninghamia lanceolata （Lamb.） Hook.〕为研究对象，对5种林分叶片、凋落叶和土壤的碳（C）、氮（N）含量（wC和wN）及其稳定碳同位素比值（δ13C）和稳定氮同位素比值（δ15N）进行比较和普通最小二乘回归分析（OLS），对不同林分叶片与土壤间δ13C和δ15N的差值（Δδ13C和Δδ15N）进行比较，并对叶片、凋落叶和土壤的wC、wN、δ13C和δ15N进行Pearson相关性分析。结果显示：5种林分中，黧蒴锥林的叶片wC及南酸枣林的叶片wN最高，杉木林的叶片δ13C和δ15N最高；壳菜果林的凋落叶wC及南酸枣林的凋落叶wN最高，杉木林的凋落叶δ13C和δ15N最高；杉木林的土壤wC、wN、δ13C和δ15N均最高。回归分析结果显示：5种林分叶片和凋落叶的δ13C与ln wC以及δ15N与ln wN均在0.001水平呈显著正相关；南酸枣林土壤的δ13C与ln wC以及壳菜果林土壤的δ15N与ln wN在0.05水平呈显著正相关，杉木林土壤的δ15N与ln wN在0.001水平呈显著正相关，其余林分土壤的δ13C与ln wC以及δ15N与ln wN均在0.01水平呈显著正相关。5种林分的Δδ13C和Δδ15N分别为-7.14‰~-5.98‰和-4.01‰~-3.36‰，且这2个指标在林分间的差异不显著。相关性分析结果显示：有34对指标的相关性达到显著（P＜0.05）或极显著（P＜0.01）水平。综合分析认为，不同叶习性树种在碳、氮分配策略上存在显著差异；比较来看，杉木林土壤的碳、氮富集效应较强，有机碳的周转和分解速率较高；稳定碳、氮同位素信号在森林生态系统养分循环过程中表现出较强的继承性和耦合性。

Taking common plantation species of Mytilaria laosensis Lecomte, Schima superba Gardner et Champ., Castanopsis fissa (Champ. ex Benth.) Rehder et E. H. Wilson, Choerospondias axillaris (Roxb.) B. L. Burtt et A. W. Hill, and Cunninghamia lanceolata (Lamb.) Hook. in northern Fujian Province as research objects, the carbon (C) and nitrogen (N) contents (wC and wN) and their stable carbon isotope ratio (δ13C) and stable nitrogen isotope ratio (δ15N) in leaves, litters, and soils of the five stands were compared and analyzed via ordinary least squares regression (OLS), the differences in δ13C and δ15N between leaves and soils (Δδ13C and Δδ15N) of different stands were compared, and the Pearson correlation analysis was conducted for wC, wN, δ13C, and δ15N in leaves, litters, and soils. The results show that leaf wC in C. fissa forest and leaf wN in C. axillaris forest are the highest, and leaf δ13C and δ15N in C. lanceolata forest are the highest. Litter wC in M. laosensis forest and litter wN in C. axillaris forest are the highest, and litter δ13C and δ15N in C. lanceolata forest are the highest. Soil wC, wN, δ13C, and δ15N  in C. lanceolata forest are the highest. The regression analysis result shows that δ13C and ln wC as well as δ15N and ln wN in leaves and litters of the five stands show significant positive correlations at 0.001 level; δ13C and ln wC in soils of C. axillaris forest and δ15N and ln wN in soils of M. laosensis forest show significant positive correlations at 0.05 level, while δ15N and ln wN in soils of C. lanceolata forest show a significant positive correlation at 0.001 level, and δ13C and ln wC as well as δ15N and ln wN in soils of the other stands show significant positive correlations at 0.01 level. Δδ13C and Δδ15N of the five stands are -7.14‰--5.98‰ and -4.01‰--3.36‰, respectively, and the differences in these two indexes  are not significant among stands. The correlation analysis result shows that the correlations of 34 pairs of indexes reach significant (P＜0.05) and extremely significant (P＜0.01) levels. The comprehensive analysis suggests that there are significant differences in carbon and nitrogen allocation strategies among the tree species with different leaf habits; in comparison, the carbon and nitrogen enrichment effects of C. lanceolata forest soil are relatively strong, and its organic carbon turnover and decomposition rates are relatively high; stable carbon and nitrogen isotope signals exhibit relatively strong inheritance and coupling during nutrient cycle processes in the forest ecosystem.