To study the historical temperature variation in Yili of Xinjiang,the tree-ring chronologies of maximum density(MXD) and tree-ring width(TRW) were established with the Schrenk Spruce(Picea schrenkiana Fisch.et Mey) co...To study the historical temperature variation in Yili of Xinjiang,the tree-ring chronologies of maximum density(MXD) and tree-ring width(TRW) were established with the Schrenk Spruce(Picea schrenkiana Fisch.et Mey) collected from six sites to analyze the characteristics and ability of response to climate change.The results suggest that the MXD chronology of the Schrenk Spruce from different sampling sites responded to climate change well and were positively correlated with the mean maximum temperature and the mean temperature from April to August in the study area.The mean maximum temperature anomaly from April to August,spanning the years from 1848 to 2000,was reconstructed by three MXD chronologies which were selected by stepwise regression.The reconstructed function was stable and explained 56.2% of the variance.The reconstructed results indicated a cold span of 153 years in spring and summer from the beginning of the 1950s to the beginning of the 1970s in the Yili valley.No strongly increasing tendency was detected in the mean maximum temperature anomaly from April to August during this reconstructed period.展开更多
Global warming causes an unstable response in tree radial growth at high latitudes in the Northern Hemisphere.Additionally,different climatic responses of different age groups of trees have been found due to their dif...Global warming causes an unstable response in tree radial growth at high latitudes in the Northern Hemisphere.Additionally,different climatic responses of different age groups of trees have been found due to their different physiological mechanisms.In this study,the response stability and growth trend of three age groups(young<100 a,middle 100-200 a,old≥200 a)of Picea schrenkiana(Schrenk spruce)to climate change and the causes of the different responses in different age groups were analyzed in the relatively dry climate of the eastern Tianshan Mountains.The results showed that:(1)With the abrupt increase in temperature in 1989,the annual mean minimum temperature became the dominant radial growth-limiting factor of the three age groups of Schrenk spruce.(2)The radial growth of the middle and young groups was more sensitive than that of the old group based on growth-climate correlation analysis.(3)The radial growth of the different age groups had different responses to climate factors,and all age groups were unstable on time scales.(4)The trend of the linear regression simulation of the basal area increment(BAI)indicated that the Schrenk spruce had the same growth trends in different age groups with growth first increased and then decreased;however,the decreased growth rate was higher in the middle and young age groups than in the old age group after the abrupt increase in temperature.Therefore,we should pay active attention to the impact of drought on Schrenk spruce in the eastern Tianshan Mountains and should particularly strengthen the conservation and management of the middle and young age groups.展开更多
[目的]为了提高森林景观模拟的真实性和实用性,为森林景观规划和森林经营管理提供可靠依据。[方法]以新疆霍城县果子沟林场作为试验区,以林区内主要树种雪岭云杉为树木建模对象,以小班为单位对果子沟林场进行三维可视化模拟。通过外业...[目的]为了提高森林景观模拟的真实性和实用性,为森林景观规划和森林经营管理提供可靠依据。[方法]以新疆霍城县果子沟林场作为试验区,以林区内主要树种雪岭云杉为树木建模对象,以小班为单位对果子沟林场进行三维可视化模拟。通过外业测量获取林木的树高、胸径、冠幅以及冠高等测树因子。从冠形和叶片角度入手对雪岭云杉的外形特征进行分析。使用单曲线方程对冠形进行模拟,使用泊松分布模型模拟树叶在树冠内的分布情况。然后,使用林相图提取小班边界。利用外业调查数据和CTS系统构建不同形态的树木模型。通过林分分布规则、小班属性以及林场内植被分布规则对林木的空间分布进行模拟。最后,使用SQL SERVER 2005作为数据管理平台,使用八叉树作为三维场景管理,结合LOD、视点替换、及地形分页等三维场景渲染及优化技术,对果子沟林场进行三维可视化模拟。模拟面积达300 km2,平均帧率20 FPS以上。[结果]模拟结果较好地反映了小班的空间分布格局,直观地体现出小班内部林木的空间位置分布,具有一定的实用价值。展开更多
全球气候变暖和大气CO_(2)浓度(Ca)急剧上升已成为不争的事实,并对森林生态系统有着深远的影响,全面理解森林生态系统对全球变化的响应至关重要。中亚干旱区特有树种雪岭云杉(Picea schrenkiana Fisch. et Mey)树轮稳定碳同位素(δ^(13...全球气候变暖和大气CO_(2)浓度(Ca)急剧上升已成为不争的事实,并对森林生态系统有着深远的影响,全面理解森林生态系统对全球变化的响应至关重要。中亚干旱区特有树种雪岭云杉(Picea schrenkiana Fisch. et Mey)树轮稳定碳同位素(δ^(13)C)和水分利用效率(iWUE)对气候变暖和大气CO2浓度急剧上升的响应缺乏研究。本研究利用天山西部伊犁河流域的雪岭云杉树轮样本,使用树木年代学方法和树轮稳定碳同位素技术,建立树轮宽度年表、稳定碳同位素(δ^(13)C)以及内禀水分利用效率(iWUE)序列,分析了树轮δ13C和iWUE的长期变化特征,探讨了树轮δ13C和iWUE对气候的响应规律以及iWUE与树轮宽度的关系。结果表明,主要的气候因子并没有强烈地限制树木径向生长;夏季平均气温对树轮δ^(13)C分馏有重要影响,iWUE的长期变化受到全球Ca增加和升温趋势影响,但直接影响iWUE年际变化的主要因素是饱和水汽压亏缺(VPD)。全球升温和Ca增加导致了iWUE的持续升高,但并没有导致雪岭云杉树木径向生长的明显增加。展开更多
基金Supported by the National Basic Research Program of China (Grant No.2009CB421307)Research Foundation of Chinese Desert Meteorology (Grant No.SQJ2006013)National Natural Science Foundation of China (Grant Nos.30270227 and J0630965)
文摘To study the historical temperature variation in Yili of Xinjiang,the tree-ring chronologies of maximum density(MXD) and tree-ring width(TRW) were established with the Schrenk Spruce(Picea schrenkiana Fisch.et Mey) collected from six sites to analyze the characteristics and ability of response to climate change.The results suggest that the MXD chronology of the Schrenk Spruce from different sampling sites responded to climate change well and were positively correlated with the mean maximum temperature and the mean temperature from April to August in the study area.The mean maximum temperature anomaly from April to August,spanning the years from 1848 to 2000,was reconstructed by three MXD chronologies which were selected by stepwise regression.The reconstructed function was stable and explained 56.2% of the variance.The reconstructed results indicated a cold span of 153 years in spring and summer from the beginning of the 1950s to the beginning of the 1970s in the Yili valley.No strongly increasing tendency was detected in the mean maximum temperature anomaly from April to August during this reconstructed period.
基金supported by the National Natural Science Foundation of China(Projects No.41861006 and 41630750)the Scientific Research Program of Higher Education Institutions of Gansu Province(2018C-02)the Research Ability Promotion Program for Young Teachers of Northwest Normal University(NWNU-LKQN2019-4)。
文摘Global warming causes an unstable response in tree radial growth at high latitudes in the Northern Hemisphere.Additionally,different climatic responses of different age groups of trees have been found due to their different physiological mechanisms.In this study,the response stability and growth trend of three age groups(young<100 a,middle 100-200 a,old≥200 a)of Picea schrenkiana(Schrenk spruce)to climate change and the causes of the different responses in different age groups were analyzed in the relatively dry climate of the eastern Tianshan Mountains.The results showed that:(1)With the abrupt increase in temperature in 1989,the annual mean minimum temperature became the dominant radial growth-limiting factor of the three age groups of Schrenk spruce.(2)The radial growth of the middle and young groups was more sensitive than that of the old group based on growth-climate correlation analysis.(3)The radial growth of the different age groups had different responses to climate factors,and all age groups were unstable on time scales.(4)The trend of the linear regression simulation of the basal area increment(BAI)indicated that the Schrenk spruce had the same growth trends in different age groups with growth first increased and then decreased;however,the decreased growth rate was higher in the middle and young age groups than in the old age group after the abrupt increase in temperature.Therefore,we should pay active attention to the impact of drought on Schrenk spruce in the eastern Tianshan Mountains and should particularly strengthen the conservation and management of the middle and young age groups.
文摘[目的]为了提高森林景观模拟的真实性和实用性,为森林景观规划和森林经营管理提供可靠依据。[方法]以新疆霍城县果子沟林场作为试验区,以林区内主要树种雪岭云杉为树木建模对象,以小班为单位对果子沟林场进行三维可视化模拟。通过外业测量获取林木的树高、胸径、冠幅以及冠高等测树因子。从冠形和叶片角度入手对雪岭云杉的外形特征进行分析。使用单曲线方程对冠形进行模拟,使用泊松分布模型模拟树叶在树冠内的分布情况。然后,使用林相图提取小班边界。利用外业调查数据和CTS系统构建不同形态的树木模型。通过林分分布规则、小班属性以及林场内植被分布规则对林木的空间分布进行模拟。最后,使用SQL SERVER 2005作为数据管理平台,使用八叉树作为三维场景管理,结合LOD、视点替换、及地形分页等三维场景渲染及优化技术,对果子沟林场进行三维可视化模拟。模拟面积达300 km2,平均帧率20 FPS以上。[结果]模拟结果较好地反映了小班的空间分布格局,直观地体现出小班内部林木的空间位置分布,具有一定的实用价值。
文摘全球气候变暖和大气CO_(2)浓度(Ca)急剧上升已成为不争的事实,并对森林生态系统有着深远的影响,全面理解森林生态系统对全球变化的响应至关重要。中亚干旱区特有树种雪岭云杉(Picea schrenkiana Fisch. et Mey)树轮稳定碳同位素(δ^(13)C)和水分利用效率(iWUE)对气候变暖和大气CO2浓度急剧上升的响应缺乏研究。本研究利用天山西部伊犁河流域的雪岭云杉树轮样本,使用树木年代学方法和树轮稳定碳同位素技术,建立树轮宽度年表、稳定碳同位素(δ^(13)C)以及内禀水分利用效率(iWUE)序列,分析了树轮δ13C和iWUE的长期变化特征,探讨了树轮δ13C和iWUE对气候的响应规律以及iWUE与树轮宽度的关系。结果表明,主要的气候因子并没有强烈地限制树木径向生长;夏季平均气温对树轮δ^(13)C分馏有重要影响,iWUE的长期变化受到全球Ca增加和升温趋势影响,但直接影响iWUE年际变化的主要因素是饱和水汽压亏缺(VPD)。全球升温和Ca增加导致了iWUE的持续升高,但并没有导致雪岭云杉树木径向生长的明显增加。
