以浙江省淳安县姥山林场（S1）和湖北省太子山林场管理局石龙林场（S2）2个试验点内10个相同种源的马尾松（Pinus massoniana Lamb.）植株为研究对象，对其长期生长过程中年轮宽度、早材宽度、晚材宽度和年轮稳定碳同位素比率（δ13C）的变化以及年轮δ13C值的种源间差异进行了比较，并对年轮δ13C值的影响因子进行了分析。结果表明：随着年轮增长，2个试验点马尾松的年轮宽度总体上先降低后略升高；S1试验点的早材和晚材宽度均先降低后略升高，而S2试验点的早材和晚材宽度则缓慢降低；2个试验点马尾松的年轮δ13C值呈“升高—降低—升高—降低”的趋势。S1和S2试验点各年轮段δ13C值的均值分别为-26.48‰～-25.19‰和-25.71‰～-25.05‰，且S2试验点各年轮段δ13C值的均值高于S1试验点。方差分析结果表明：马尾松各年轮段δ13C值的均值在种源间差异极显著（P＜0.01）；总体上看，高纬度地区种源各年轮段的δ13C值依次高于中纬度和低纬度地区种源。相关性分析结果表明：2个试验点马尾松年轮δ13C值与种源地的纬度和干燥度指数呈显著（P＜0.05）正相关，与种源地的年均温、年降水量、5月至9月降水量和≥10 ℃年积温以及种源地和试验点间纬度差值呈显著负相关，与年轮宽度和早材宽度呈显著或极显著负相关，与晚材宽度呈不显著负相关。研究结果显示：马尾松年轮δ13C值在种源间变异丰富，这是其对种源地环境长期适应的结果；立地环境和径向生长对马尾松固碳过程中碳同位素的分馏有一定影响。

 Taking plants of Pinus massoniana Lamb. from ten identical provenances in two test sites of Laoshan Forest Farm in Chunan County of Zhejiang Province （S1） and Shilong Forest Farm in Taizishan Forest Farm Administration of Hubei Province （S2） as research objects， the variations of ring width， early wood width， late wood width and ring stable carbon isotope ratio (δ13C) value during its longterm growth process and the differences in ring δ13C value among provenances were compared， and the factors affecting ring δ13C value were analyzed. The results show that with the increase of ring， ring width of P. massoniana in two test sites firstly decreases and then increases slightly in general； early and late wood widths in S1 test site both firstly decrease and then increase slightly， while those in S2 test site decrease slowly； ring δ13C value of P. massoniana in two test sites shows a tendency of “increase-decrease-increase-decrease”. The means of δ13C value of different ring segments in S1 and S2 test sites are -26.48‰ - -25.19‰ and -25.71‰ - -25.05‰， respectively， and the mean of δ13C value of different ring segments in S2 test site is higher than that in S1 test site. The variance analysis result shows that there are extremely significant （P＜0.01） differences in means of δ13C value of different ring segments of P. massoniana among provenances； overall， δ13C value of different ring segments from provenances in high latitude area is successively higher than that from provenances in middle and low latitude areas. The correlation analysis result shows that ring δ13C value of P. massoniana in two test sites shows significant （P＜0.05） positive correlations with latitude and aridity index of provenance locality， significant negative correlations with annual mean temperature， annual precipitation， precipitation from May to September and ≥10 ℃ annual accumulated temperature and latitude difference between provenance locality and test site， significant or extremely significant negative correlations with ring width and early wood width， and unsignificant negative correlation with late wood width. It is suggested that the variation of ring δ13C value of P. massoniana among different provenances is rich， which is a result of long-term adaption to environment of provenance locality. Site environment and radial growth both have some effects on fractionation of carbon isotope during nitrogen fixation process of P. massoniana.