Two tree-ring MXD (maximum latewood density) chronologies of Abies fabri were developed from the eastern slopes of Gongga Mountain, and a regional chronology (RC) was established based on the two MXD chronologies. The...Two tree-ring MXD (maximum latewood density) chronologies of Abies fabri were developed from the eastern slopes of Gongga Mountain, and a regional chronology (RC) was established based on the two MXD chronologies. There were significant positive correlations between the three MXD chronologies and August-September temperature, and the RC had the highest correlation (r=0.733, n=48, P<0.001) with mean August-September temperature. Based on growth-climate analyses, we reconstructed mean August-September temperature during the past 171 years for the study area. The reconstruction explained 53.5% of the instrumental temperature variance during the period 1960-2007 (F=52.8, R2adj =52.4%). In the past 171 years, there were 22 very warm years and 23 very cold years, four cold periods (1837-1842, 1884-1891, 1899-1905 and 1984-1989) and three warm periods (1966-1973, 1916-1924 and 1876-1881). Our reconstruction was validated by other tree ring-based temperature reconstructions from the surrounding area and documented climate disaster events.展开更多
Streamwater chemistry and spatial flow dynamics from a subalpine Abies fabri forest in an experimental watershed located in the east slope of Gongga Mountain were analyzed to gain insights into the gradient effect of ...Streamwater chemistry and spatial flow dynamics from a subalpine Abies fabri forest in an experimental watershed located in the east slope of Gongga Mountain were analyzed to gain insights into the gradient effect of primary community succession on the stream biogeochemical process. Results showed that high sand content(exceeding 80%) and porosity in the soil(exceeding 20% in A horizon and 35% in B horizon), as well as a thick humus layer on the soil surface, made the water exchange quickly in the Huangbengliu(HBL) watershed. Consequently, no surface runoff was observed, and the stream discharge changed rapidly with the daily precipitation. The flow trends of base ions in the stream water were influenced by the Abies fabri succession gradient. Ca 2+ , HCO - 3 and SO 2- 4 were the dominant anions in the streamwater in this region. A significant difference of Ca 2+ , HCO - 3 and SO 2- 4 concentration exported between the succession stages in the watershed can be found. But they had the similar temporal change in the stream flow. Ca 2+ , HCO - 3 and SO 2- 4 showed significantly negative correlations with the daily precipitation and the stream discharge. \;Concentrations of Cl -, Na +, K +, and Mg 2+ were low in all streamwaters monitored and we observed no differences along the Abies fabri succession gradient. Low ratios of Na:(Na+Ca) (range from 0.1 to 0.2) implied cations were from bedrock weathering(internal source process in the soil system) in this region. But, a variance analysis showed there were almost no differences between rainwater and streamwaters for Mg 2+ , Na +, K +, and Cl - concentrations. This indicated that they might be come from rainfall inputs(external source). The highly mobile capacity, rapid water exchange between precipitation and discharge, and long-term export lead to this observed pattern were suggested.展开更多
The hydrological character parameters of the litter amount, the maximum water capacity and water absorption speed of the litter on the forest land under four type of \%Abies fabri\% forest (young, half_mature,mature a...The hydrological character parameters of the litter amount, the maximum water capacity and water absorption speed of the litter on the forest land under four type of \%Abies fabri\% forest (young, half_mature,mature and overmature stand)on the Gongga Mountain were studied in this paper. The result showed that the litter amount under the overmature stand was the maximum(67 8?t·hm -2 ), the second was the mature stand(53 4 t·hm -2 ), the third was the half mature stand(40 4 t·hm -2 ), the fourth was the young stand(32 6?t·hm -2 ). The maximum water capacity of the undecomposed litter under the mature stand was 428 8% of the litter’s dry weight, that of the litter under the overmature stand was 411 6%, that of the litter under the half_mature stand was 378 8%, that of the litter under the young stand was 296 7%. The maximum water capacity of the half_decomposed litter under the mature stand was 234 5% of the litter’s dry weight, that of the litter under the overmature stand was 175 6%, that of the litter under the half mature stand was 160 3%, that of the litter under the young stand was 132 5%. The equation between the water absorption speed of the litter and the soaked time is S=kt n. The result also shows that the litter’s variation with the time has no relation to forest age, while its decomposition degree is positively related to stand age.展开更多
贡嘎山位于青藏高原和四川盆地的过渡带。峨眉冷杉林是贡嘎山暗针叶林的重要组成部分。采用规范的调查监测方法获取峨眉冷杉土壤物理性质和元素对直接揭示土壤质量的变化具有重要意义,也为模拟山地生态系统物质循环过程提供参数。中国...贡嘎山位于青藏高原和四川盆地的过渡带。峨眉冷杉林是贡嘎山暗针叶林的重要组成部分。采用规范的调查监测方法获取峨眉冷杉土壤物理性质和元素对直接揭示土壤质量的变化具有重要意义,也为模拟山地生态系统物质循环过程提供参数。中国科学院贡嘎山高山生态系统观测试验站(简称“贡嘎山站”)是中国生态系统研究网络(Chinese Ecosystem Research Network,CERN)和国家生态系统观测研究网络(National Ecosystem Research Network of China,CNERN)共同建立的以亚高山生态、土壤、水文、气候、冰川为一体的综合性试验研究基地与观测平台。按照CERN的统一规范,贡嘎山站开展了土壤长期监测工作。本数据集收集整理了2005–2015年峨眉冷杉林0–10、10–20、20–40、40–60、60–100 cm土层土壤的容重、机械组成、土壤养分全量、土壤矿质全量、微量元素全量、重金属全量等31项指标,其中土壤养分全量采样频率为5年/次,其他采样频率为10年/次。本数据集可为山地大气–土壤–植物生物地球化学循环过程提供基础数据,为山地生态安全和生态修复提供理论参考。展开更多
成熟森林的碳收支对陆地生态系统碳循环研究具有重要意义。目前,我国关于西南亚高山暗针叶林成熟林碳通量的研究还相对较少,尚不明确对碳循环的作用。以涡度相关技术为基础,对川西贡嘎山东坡峨眉冷杉成熟林生态系统尺度的CO_2通量进行...成熟森林的碳收支对陆地生态系统碳循环研究具有重要意义。目前,我国关于西南亚高山暗针叶林成熟林碳通量的研究还相对较少,尚不明确对碳循环的作用。以涡度相关技术为基础,对川西贡嘎山东坡峨眉冷杉成熟林生态系统尺度的CO_2通量进行长期定位观测。利用2015年6月至2016年5月观测数据,分析了峨眉冷杉成熟林净生态系统CO_2交换量(NEE)、生态系统呼吸(Re)和总生态系统生产力(GPP)的季节变异特征及其源汇状况,并结合环境因子,分析CO_2通量的主要控制因子。结果表明:(1)峨眉冷杉成熟林NEE具有明显的日变化特征,呈现"U"形变化,白天为负值,夜间为正值,中午前后CO_2通量达到最大;各月间日平均NEE变化差异显著,NEE峰值最大出现在2015年6月(-0.64 mg CO_2m^(-2)s^(-1)),峰值最小出现在2016年1月(-0.08 mg CO_2m^(-2)s^(-1));日平均NEE由正值变为负值的时间夏季最早,冬季最晚,NEE由负值变为正值的时间冬季最早,夏季最晚。(2)峨眉冷杉成熟林NEE、Re和GPP具有明显的月变化。2015年6月和12月NEE分别达到最大值(-46.02 g C m^(-2)月^(-1))和最小值(-1.42 g C m^(-2)月^(-1));Re呈现单峰变化,最大和最小值分别出现在2015年6月(84.78 g C m^(-2)月^(-1))和2016年1月(12.82 g C m^(-2)月^(-1));GPP最大值和最小值分别出现在2015年6月(130.81 g C m^(-2)月^(-1))与2016年1月(16.15 g C m^(-2)月^(-1))。(3)空气温度(T_a)、5 cm土壤温度(T_(s5))和光合有效辐射(PAR)是影响峨眉冷杉成熟林CO_2通量的主要环境因子。T_a与CO_2通量呈指数相关(R^2=0.5283,P<0.01);白天CO_2通量与PAR显著相关(R^2=0.4373,P<0.01);夜晚CO_2通量与T_(s5)显著相关(R^2=0.4717,P<0.01)。(4)全年NEE、Re和GPP分别为-241.87、564.81 g C m^(-2)和806.68 g C m^(-2),表明川西贡嘎山峨眉冷杉成熟林具有较强的碳汇功能。展开更多
基金supported by the Science and Technology Ministry Commonwealth Trade (Meteorology) Scientific Research Specialized Project (GYHY200806011)the National Basic S&T Project of the Ministry of Science and Technology of China (2007FY220200)the National Natural Science Foundation of China (40871058)
文摘Two tree-ring MXD (maximum latewood density) chronologies of Abies fabri were developed from the eastern slopes of Gongga Mountain, and a regional chronology (RC) was established based on the two MXD chronologies. There were significant positive correlations between the three MXD chronologies and August-September temperature, and the RC had the highest correlation (r=0.733, n=48, P<0.001) with mean August-September temperature. Based on growth-climate analyses, we reconstructed mean August-September temperature during the past 171 years for the study area. The reconstruction explained 53.5% of the instrumental temperature variance during the period 1960-2007 (F=52.8, R2adj =52.4%). In the past 171 years, there were 22 very warm years and 23 very cold years, four cold periods (1837-1842, 1884-1891, 1899-1905 and 1984-1989) and three warm periods (1966-1973, 1916-1924 and 1876-1881). Our reconstruction was validated by other tree ring-based temperature reconstructions from the surrounding area and documented climate disaster events.
文摘Streamwater chemistry and spatial flow dynamics from a subalpine Abies fabri forest in an experimental watershed located in the east slope of Gongga Mountain were analyzed to gain insights into the gradient effect of primary community succession on the stream biogeochemical process. Results showed that high sand content(exceeding 80%) and porosity in the soil(exceeding 20% in A horizon and 35% in B horizon), as well as a thick humus layer on the soil surface, made the water exchange quickly in the Huangbengliu(HBL) watershed. Consequently, no surface runoff was observed, and the stream discharge changed rapidly with the daily precipitation. The flow trends of base ions in the stream water were influenced by the Abies fabri succession gradient. Ca 2+ , HCO - 3 and SO 2- 4 were the dominant anions in the streamwater in this region. A significant difference of Ca 2+ , HCO - 3 and SO 2- 4 concentration exported between the succession stages in the watershed can be found. But they had the similar temporal change in the stream flow. Ca 2+ , HCO - 3 and SO 2- 4 showed significantly negative correlations with the daily precipitation and the stream discharge. \;Concentrations of Cl -, Na +, K +, and Mg 2+ were low in all streamwaters monitored and we observed no differences along the Abies fabri succession gradient. Low ratios of Na:(Na+Ca) (range from 0.1 to 0.2) implied cations were from bedrock weathering(internal source process in the soil system) in this region. But, a variance analysis showed there were almost no differences between rainwater and streamwaters for Mg 2+ , Na +, K +, and Cl - concentrations. This indicated that they might be come from rainfall inputs(external source). The highly mobile capacity, rapid water exchange between precipitation and discharge, and long-term export lead to this observed pattern were suggested.
文摘The hydrological character parameters of the litter amount, the maximum water capacity and water absorption speed of the litter on the forest land under four type of \%Abies fabri\% forest (young, half_mature,mature and overmature stand)on the Gongga Mountain were studied in this paper. The result showed that the litter amount under the overmature stand was the maximum(67 8?t·hm -2 ), the second was the mature stand(53 4 t·hm -2 ), the third was the half mature stand(40 4 t·hm -2 ), the fourth was the young stand(32 6?t·hm -2 ). The maximum water capacity of the undecomposed litter under the mature stand was 428 8% of the litter’s dry weight, that of the litter under the overmature stand was 411 6%, that of the litter under the half_mature stand was 378 8%, that of the litter under the young stand was 296 7%. The maximum water capacity of the half_decomposed litter under the mature stand was 234 5% of the litter’s dry weight, that of the litter under the overmature stand was 175 6%, that of the litter under the half mature stand was 160 3%, that of the litter under the young stand was 132 5%. The equation between the water absorption speed of the litter and the soaked time is S=kt n. The result also shows that the litter’s variation with the time has no relation to forest age, while its decomposition degree is positively related to stand age.
文摘贡嘎山位于青藏高原和四川盆地的过渡带。峨眉冷杉林是贡嘎山暗针叶林的重要组成部分。采用规范的调查监测方法获取峨眉冷杉土壤物理性质和元素对直接揭示土壤质量的变化具有重要意义,也为模拟山地生态系统物质循环过程提供参数。中国科学院贡嘎山高山生态系统观测试验站(简称“贡嘎山站”)是中国生态系统研究网络(Chinese Ecosystem Research Network,CERN)和国家生态系统观测研究网络(National Ecosystem Research Network of China,CNERN)共同建立的以亚高山生态、土壤、水文、气候、冰川为一体的综合性试验研究基地与观测平台。按照CERN的统一规范,贡嘎山站开展了土壤长期监测工作。本数据集收集整理了2005–2015年峨眉冷杉林0–10、10–20、20–40、40–60、60–100 cm土层土壤的容重、机械组成、土壤养分全量、土壤矿质全量、微量元素全量、重金属全量等31项指标,其中土壤养分全量采样频率为5年/次,其他采样频率为10年/次。本数据集可为山地大气–土壤–植物生物地球化学循环过程提供基础数据,为山地生态安全和生态修复提供理论参考。
文摘成熟森林的碳收支对陆地生态系统碳循环研究具有重要意义。目前,我国关于西南亚高山暗针叶林成熟林碳通量的研究还相对较少,尚不明确对碳循环的作用。以涡度相关技术为基础,对川西贡嘎山东坡峨眉冷杉成熟林生态系统尺度的CO_2通量进行长期定位观测。利用2015年6月至2016年5月观测数据,分析了峨眉冷杉成熟林净生态系统CO_2交换量(NEE)、生态系统呼吸(Re)和总生态系统生产力(GPP)的季节变异特征及其源汇状况,并结合环境因子,分析CO_2通量的主要控制因子。结果表明:(1)峨眉冷杉成熟林NEE具有明显的日变化特征,呈现"U"形变化,白天为负值,夜间为正值,中午前后CO_2通量达到最大;各月间日平均NEE变化差异显著,NEE峰值最大出现在2015年6月(-0.64 mg CO_2m^(-2)s^(-1)),峰值最小出现在2016年1月(-0.08 mg CO_2m^(-2)s^(-1));日平均NEE由正值变为负值的时间夏季最早,冬季最晚,NEE由负值变为正值的时间冬季最早,夏季最晚。(2)峨眉冷杉成熟林NEE、Re和GPP具有明显的月变化。2015年6月和12月NEE分别达到最大值(-46.02 g C m^(-2)月^(-1))和最小值(-1.42 g C m^(-2)月^(-1));Re呈现单峰变化,最大和最小值分别出现在2015年6月(84.78 g C m^(-2)月^(-1))和2016年1月(12.82 g C m^(-2)月^(-1));GPP最大值和最小值分别出现在2015年6月(130.81 g C m^(-2)月^(-1))与2016年1月(16.15 g C m^(-2)月^(-1))。(3)空气温度(T_a)、5 cm土壤温度(T_(s5))和光合有效辐射(PAR)是影响峨眉冷杉成熟林CO_2通量的主要环境因子。T_a与CO_2通量呈指数相关(R^2=0.5283,P<0.01);白天CO_2通量与PAR显著相关(R^2=0.4373,P<0.01);夜晚CO_2通量与T_(s5)显著相关(R^2=0.4717,P<0.01)。(4)全年NEE、Re和GPP分别为-241.87、564.81 g C m^(-2)和806.68 g C m^(-2),表明川西贡嘎山峨眉冷杉成熟林具有较强的碳汇功能。
