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
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。
