对大兴安岭北部两株樟子松(Pinus sylvestris var.mongolica)树轮样品的年内稳定碳同位素比率(δ13C)进行测定,结果表明:樟子松树轮年内δ13C值在不同生长阶段总体表现出每年生长季中期最高、早期次之、晚期最低的变化特征。δ13C的年内变化趋势在幼龄期至速生期变化剧烈,成熟期至衰老期相对平缓。从幼龄期至衰老期的整个生长阶段,同时期年内δ13C的变动幅度基本为晚材大于早材。幼龄期年内晚材的δ13C一直明显高于早材,而成熟期年内早晚材δ13C的差别逐渐减小,至衰老期年内晚材δ13C已低于早材且无显著差别。树轮δ13C的年内变化主要体现在生长季中后期,即早晚材之间的过渡段至晚材。年内不同时段的δ13C序列与同时段的宽度去除生长趋势序列(去趋势序列)之间的相关性随生长季节的推移而逐渐降低。当年早材宽度与前一年晚材宽度显著正相关,当年早材δ13C序列与前一年晚材宽度和当年早材宽度的去趋势合并序列呈现较显著的负相关性,与前一年晚材δ13C序列或宽度去趋势序列之间均未表现出显著的相关性。分析结果表明:早材的形成很可能来源于前一年光合作用的产物,在利用树轮年内不同材质宽度或δ13C序列进行气候环境重建时需要考虑这一点。年内早材、过渡段和晚材三个时段的δ13C分别对应于4月下旬至6月中旬土壤湿度较大、温度上升较快的时期,6月下旬至7月中旬降水增加、温度达到最高而相对湿度降低的时期,以及7月下旬至9月中旬降水增加、温度下降而相对湿度较大的时期。 The annual stable carbon isotope ratio (δ13C) of two Pinus sylvestris var. Mongolica tree round samples in the northern part of the Greater Xing’an Mountains was measured. The results showed that the δ13C value of Pinus sylvestris var. Mongolica showed an annual growth season at different growth stages Middle highest, early second, late lowest change. The trend of δ13C during the year varied sharply from young to fast-growing, and was relatively flat from maturity to senescence. During the whole growth phase from young age to senescence, the change of δ13C during the same period was basically that latewood was bigger than earlywood. The δ13C of early wood during early years was significantly higher than that of early wood, while the difference of δ13C between early and late wood during maturity was gradually reduced. However, δ13C of late wood was lower than that of earlywood during the year of aging. Tree-ring δ13C changes during the year mainly reflected in the late growth season, that is, the transition between early and late wood to latewood. The correlation between the δ13C sequence at different periods of the year and the width-removed growth trend sequence (de-trend sequence) at the same time gradually decreased with the growing season. There was a significant positive correlation between the width of the earlywood and the width of the latewood of the previous year. The δ13C sequence of the earlywood showed a significant negative correlation with the sequence of the latewood width and the width of the earlywoodwood of the previous year, No significant correlation was observed between the δ13C sequence and the width to trend sequence. The results show that the formation of earlywood is likely to be the product of photosynthesis in the previous year, which needs to be considered in the reconstruction of climatic environment using different material widths or δ13C sequences during the tree ring year. During the year, the δ13C values ​​of the early wood, the transitional wood and the late woody woodland correspond to the periods of relatively high soil moisture and rapid temperature rise in late April to mid-June respectively. The precipitation increased from late June to mid-July and the temperature reached the highest The period of decreasing relative humidity, and the period of increasing precipitation in late July to mid-September with the temperature decreasing and the relative humidity larger.