Oxygen and carbon isotopic ratios of tree-ring cellulose in a conifer-hardwood mixed forest in northern Japan
Oxygen and carbon isotopic ratios of tree-ring cellulose in a conifer-hardwood mixed forest in northern Japan
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DOI：
10.2343/geochemj.38.77
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发表时间：
2004-02
影响因子：
0.8
通讯作者：
T. Nakatsuka;K. Ohnishi;T. Hara;A. Sumida;Daisuke Mitsuishi;N. Kurita;S. Uemura
中科院分区：
文献类型：
--
作者：
T. Nakatsuka;K. Ohnishi;T. Hara;A. Sumida;Daisuke Mitsuishi;N. Kurita;S. Uemura
在日本北方亚寒带针叶-阔叶混交林中，对5株皱叶栎（Quercus crispula）和4株冷杉（Abies sachalinensis）年轮中纤维素的氧、碳同位素（δ 18 O和δ 13 C）进行了分析。δ 18 O的变异在各树种间具有较好的相关性。crispula（林冠树）和A. sachalinensis（最近长大的亚冠层树木），虽然A. sachalinensis的δ 18 O值比Q高约1 ‰。两种鱼类的δ 18 O变化存在明显的1年相位滞后。不同个体和种间δ 18 O的年际变化相似，表明受共同的环境控制。与δ 18 O相反，δ 13 C的年际变化在单株之间没有任何共同的趋势。crispula或A. sachalinesis，表明生态效应，如δ 13 C的空间异质性和/或冠层空气中的CO2浓度和/或与相邻树木的光竞争，调节每棵树光合产物的δ 13 C。结果表明：1.水曲柳年轮中δ 18 O和δ 13 C的季节变化结果表明，皱鳃分别具有随机性和周期性特征。δ 18 O和δ 13 C的年变化模式之间的差异支持了δ 18 O受某些环境因素控制的观点，这些环境因素每年都在变化，但δ 13 C主要受树木本身的生理条件控制，这些条件在每个生长季节都有规律地重复。研究了杉木年轮纤维素δ ~（18）O的历史变化。与冬、夏季降水量呈负相关，而与气温无明显相关，可能与研究区降水的多水汽源地有关。由于日本北方降水的δ 18 O与气温呈正相关，因此δ 18 O与冬季降水的相关性表明，在一个大雪年，该森林的土壤中保留了大量来自融雪的低δ 18 O水，这些水被Q的根系吸收。夏天的皱叶菜另一方面，与夏季降水量的负相关不能用降水的δ 18 O来解释，而必须用夏季降水量大的年份中生长季的相对湿度较高来解释。研究结果证实了树轮纤维素δ 18 O在重建强降雪森林中过去气候的潜力，并表明了大气-土壤-植物系统水文知识对于利用树轮δ 18 O进行古环境研究的重要性。
Oxygen and carbon isotopic ratios (δ18O and δ13C) were analyzed for cellulose extracted from tree rings of 5 oak trees (Quercus crispula) and 4 fir trees (Abies sachalinensis) standing in a 1 ha plot of a sub-boreal conifer-hardwood mixed forest, northern Japan. The δ18O variations were well correlated between individual trees of Q. crispula (canopy trees) and A. sachalinensis (recently grown-up sub-canopy trees), although A. sachalinensis had about 1 ‰ higher δ18O values than Q. crispula on average and there was an apparent one-year phase lag between δ18O variations of the two species. The similar inter-annual variation in δ18O among different individuals and species suggests a common environmental control. Contrary to δ18O, the inter-annual variations in δ13C did not possess any common trends among individual trees for either Q. crispula or A. sachalinesis, suggesting that the ecological effects, such as spatial heterogeneities in δ13C and/or concentration of CO2 in canopy air and/or competition for light with neighboring trees, regulate the δ13C of photosynthetic products in each tree. Seasonal variations of the δ18O and δ13C within annual tree rings of Q. crispula showed random and cyclic characteristics, respectively. The difference between the annual patterns of δ18O and δ13C supports the idea that δ18O is controlled by some environmental factors, which change from year to year, but δ13C is primarily governed by physiological conditions of the tree itself, which repeat regularly in every growing season. The historical variation in δ18O of tree-ring cellulose in Q. crispula has negative correlations with those in both of winter and summer precipitation amounts, whereas it does not show any relationship with temperature, probably due to multiple source areas of water vapor for the precipitation at the studied area. Because the δ18O of precipitation in northern Japan is positively correlated with air temperature, the correlation between δ18O and winter precipitation suggests that, in a year of heavy snowfall, the soil in this forest retains larger amount of lower δ18O water derived from snowmelt, which is taken by roots of Q. crispula in summer. On the other hand, the negative correlation with summer precipitation cannot be elucidated by the δ18O of rainfall, but must be explained by a higher relative humidity in the growing season in a year of larger summer rainfall. Our results confirm the potential of δ18O of tree-ring cellulose to reconstruct past climate in a forest with a heavy snowfall, and suggest the importance of the hydrological knowledge in an atmosphere-soil-plant system for the utilization of tree-ring δ18O in paleoenvironmental purposes.