树轮长年表在全球变化相关领域中的应用研究进展-以14C曲线校正、环境考古和地质灾害事件定年为例

近几十年树轮年代学得到了迅速发展,现已成功建立了大量长度逾千年的树轮长年表。本文评述树轮长年表在全球变化相关研究领域中的应用。树轮长年表可为¹⁴C定年提供校准曲线,从而将样本的¹⁴C年龄转化为日历年龄,提高了¹⁴C测年的精度;也可为环境考古如古木建筑及墓葬等提供定年服务,确定古木构建筑的建造年代;树轮长年表在地质灾害事件定年方面也发挥了重要作用。然而,树轮长年表在上述研究领域的应用也存在不足,最新的国际¹⁴C会议公布的¹⁴C校正曲线中能够准确定年的树轮校正部分仅为过去12 410年,目前尚无法提供更长时间尺度的树轮校正曲线。在对木构建筑进行定年时受到古木样本量不足的限制等。因此,为了更好地发挥树轮长年表的应用潜力,应不断发掘与延长现有树轮宽度长年表,同时建立长年表的C、O同位素序列,以期为长年表的应用不断做出贡献。     

大别山地区黄山松和油松树轮宽度的气候意义

本文基于2010年采自大别山地区黄山松、油松树轮资料分别建立了树轮宽度标准年表,利用相关函数检验了年表与附近的麻城气象站1959-2009年月平均最高气温、月平均气温、月平均最低气温和月降水量之间关系,旨在探讨黄山松、油松树轮宽度的气候意义。研究结果显示,平均敏感度、标准差、信噪比等统计量黄山松年表均高于油松年表,表明黄山松年表较油松年表包含更多的气候信息,具有更高的树轮气候学研究价值。黄山松径向生长主要受当年2-7月平均气温限制,任何月份及月份组合降水量对黄山松径向生长的限制作用均不显著;油松径向生长主要受当年5-6月降水总量限制,任何月份及月份组合气温对油松径向生长的限制作用均不显著。研究表明,在中国亚热带暖湿地区,气候要素的年际变化亦可对部分树种径向生长具有较强的限制作用,树木年轮宽度的变化对气候具有指示意义。研究结果将进一步弥补中国亚热带暖湿地区树轮宽度年表的不足,为树轮气候重建研究提供参考和依据。     

柴达木盆地东缘祁连圆柏轮宽序列标准化的方法研究

利用在青海柴达木盆地东缘山地获取的大量祁连圆柏树轮资料,对拟合并去除树木生长趋势即标准化方法进行探讨,提出了一种总体曲线方法。该方法用包含完整树木髓心、并且在40~60年间达到生长顶峰的树轮资料拟合柴达木盆地东缘祁连圆柏的总体生长趋势曲线,并用广义的负指数函数来描述树木自茎的次生生长开始以来的径向生长过程。用相同的树轮资料建立估算缺失轮数的最初径向生长模型,其方差解释量高达90.9%。建立年表时包含髓心的样芯认定生理年龄为1年,不包含髓心的样芯用最初径向生长模型估算缺失轮数,然后全部样芯用生长趋势曲线对应部分进行去趋势标准化。该方法对建立可靠、准确的长年表有重要意义,所建年表比用传统负指数函数方法建立的年表保留了更多的低频变化信息。     

五个中国特有针叶树种树轮宽度对气候变化的敏感性

本文对采自四川西部的鳞皮冷杉、铁杉、红豆杉、高山松和青海东部的青海云杉等5个中国特有针叶树种树轮宽度对气候变化的敏感性进行了研究。这五5个针叶树种的年轮纹印清晰,伪年轮和丢年轮较少(麦秀云杉0.247%,飞水崖红豆杉0.202%),便于确定年代和量测宽度,用COFECHA程序对定年结果进行检验,证明交叉定年的结果是可靠的。统计分析结果显示,这5个中国特有种差值年表包含丰富的气候信息。相关分析显示,树轮宽度数据和气象数据有着显著的相关关系。5个树种对气候因子较为敏感的响应表明,它们是适于进行树轮气候学分析的树种;在树轮气候学的研究中具有很大的潜力和应用前景。     

长白山红松和落叶松树轮宽度年表特征

利用采自长白山红松和落叶松分布上限和下限的树轮样本,分别建立树轮宽度差值年表.结果表明:下限红松年表的平均敏感度、树轮宽度指数的年际变率、信噪比等年表特征值比上限年表的高,表明下限红松生长对环境的敏感性大于上限;落叶松年表特征值在不同海拔表现与红松相反.进一步分析发现分布上限和下限的红松生长与气候因子之间的关系不同.下...     

新疆天山西部三个云杉上树线树轮最大密度年表的研制、相关性及其气候信号分析

针对新疆天山西部伊犁、博尔塔拉蒙古自治区州三大山体北坡云杉上树线树木年轮最大密度资料,采用区域曲线、负指数曲线、样条函数三种不同生长去趋势方法,研制树轮最大密度年表,分析不同采点和树轮去趋势方法对树轮最大密度年表在不同频域的相关性及气候信号的影响发现:①三个采点间的最大树轮密度变化,在高频变化方面最为相似,低频变化存在着较大差异;②天山西部山脉北坡上树线的树轮最大密度年表对年表研制的三种不同去趋势方法不敏感,而采点间的距离和是否位于同一气候区是影响上树线树轮最大密度年表间相关性的重要因子;③天山西部山脉北坡上树线的树轮最大密度年表对当年的温度具有显著的相关性,年降水量越多的山区,其上树线最大密度年表对温度的相关性越好,且显著相关平均温度涉及的月数也不断增多.     

采点和去趋势方法对天山西部云杉上树线树轮宽度年表相关性及其气候信号的影响

针对新疆天山西部伊犁、博州三大山体北坡云杉上树线树木年轮资料,采用区域曲线、负指数曲线、样条函数三种不同生长去趋势方法,研制树轮宽度年表,分析不同采点和树轮去趋势方法对树轮宽度年表在不同频域的相关性及气候信号的影响发现：①采点间的距离和是否位于同一气候区是影响云杉上树线树轮宽度年表间相关性的首要因子。三个采点间的树轮宽度变化,在高频变化方面最为相似,低频变化存在着较大差异,表明它们在揭示和重建大范围的高频气候变化方面可能具有较大的应用潜力。②三种不同去趋势方法对天山西部山脉北坡上树线的云杉树轮宽度年表的研制具有一定影响,负指数和样条函数去趋势方法研制的树轮年表较为相似,而区域曲线去趋势方法研制的树轮宽度年表中则可保留较多的轮宽低频变化信息。③降水是天山西部云杉上树线的树轮宽度生长的主要限制因子,且树轮宽度生长对降水的响应具有显著的滞后性。④在天山西部的云杉上树线采点,使用区域曲线去趋势方法有利于在树轮宽度年表中保留较多的与水分有关的气候信息。     

采用树木年轮资料重建山东沂山地区200多年来的湿润指数*

在中国,尤其在中国西北部地区,树轮年表是古气候信息的一个重要来源.由于某种原因,中国东部地区少有树轮研究工作.该文通过运引ARSTAN程序,建立并研究了山东境内沂山地区的树轮主年表(1750～1992).树轮和气候要素的响应面分析得出沂山地区的树轮生长和温度降水呈非线性相关,因此使用传统方法重建单个气候因子是不合理的.通过响应函数和回归分析,5月至8月份的湿润指数(P/T)被确定为重建对象,该湿润指数值代表了温度和降水对树轮生长的共同影响,且相关性很高,远超过信度检验.利用线性回归方法,获得重建湿润指数的预报方程,用树木年轮年表重建了自1750年以来的沂山地区逐年5月～8月湿润指数的变化.分析了沂山地区湿润指数重建的可靠性.     

乌鲁木齐河山区流域树轮宽度年表特征及其对气候的响应

通过对比乌鲁木齐河山区流域8个天山云杉树轮宽度标准化年表的多个特征参数及分析树轮年表对气候的响应,主要得到如下研究结论:(1)在8个树轮宽度年表中,东白杨沟下年表包含的气候信息最多,其次是英雄桥沟年表,再次是跃进桥东年表;(2)乌鲁木齐河山区流域气候对树木年轮生长的影响存在明显的持续性,持续年数大多为3~8 a,最短为2 a;(3)在乌鲁木齐河山区流域低海拔处气候对树木年轮宽度生长的限制作用强于高海拔地区,森林下部林缘年表中含有的气候信息多于森林上树线附近的年表;(4)通过相关函数和相关普查发现,乌鲁木齐河山区流域影响森林上树线树轮宽度年表树轮生长的主要气候限制因子是2~3月的平均温度,而影响森林下部林缘树轮宽度年表树轮生长的主要气候限制因子为5~6月的干旱强度;(5)区域森林上树线树轮宽度年表的年轮指数343 a经历了9个轮宽指数偏高时段和8个偏低时段,反映了2~3月的温度的长期变化。区域森林下部林缘树轮宽度年表的年轮指数365 a来有11个轮宽指数偏高时段和11个偏低时段,揭示了5~6月PDSI的长期变化。     

南岭华南五针松树轮宽度对气候因子的响应

应用树轮气候学研究方法建立了广东南岭地区华南五针松(Pinus kwangtungensis)树轮宽度的标准年表和差值年表。选用1965—2013年7月至当年12月的月平均温度、月最高温度、月最低温度、月降水量和月平均相对湿度作为气候因子,研究华南五针松树轮宽度对这些气候因子的响应。结果表明:华南五针松差值年表各项统计参数优于标准年表,更适于与气候因子进行相关分析;华南五针松树轮宽度对温度变化的响应比降水更敏感;影响华南五针松径向生长的主要限制因子是春季(2—4月)温度(正相关),其次是春季相对湿度(负相关)和夏季(5—8月)降水(正相关)。     

Drought is the major limiting factor for tree-ring growth of high-altitude Canary Island pines on Tenerife

This is a detailed study of 50 wood cores sampled from 25 Canary Island pines ( Pinus canariensis ) growing in a subtropical climate close to the tree limit (at Lomo de Retamar, 2000–2100 m a.s.l.) on the southern, leeward side of Tenerife.
The Canary Island pines form tree-rings and, similarly to temperate pines, earlywood is formed during spring. But many pines fail to form tree-rings every year and one purpose for this paper has been to find a way to overcome this problem. Another purpose has been to see what correlations, if any, exist between the ring widths and meteorological data. Meteorological data have been collected since 1916 at the nearby Izaña meteorological observatory. It was also important to find the limiting factor for growth of Canary Island pines close to the tree limit.
Through cross-dating, missing rings were found to be typical for younger parts of older trees; in the same years younger trees instead had low growth. Some trees lacked more than 20 rings in a century. This study shows that it is possible to compensate for missing rings, at least when the number of missing rings is less than 10%.
Correlation studies showed that the growth of the tree rings was mainly due to the precipitation factor, particularly the annual precipitation one year before the ring formation, but also due to temperature. Strangely enough, multiple linear regression gave the highest correlation coefficient (0.50) for a combination of annual precipitation one year earlier and temperature four years earlier.     

基于树轮生理模型的雪岭云杉径向生长的模拟研究

雪岭云杉（Picea schrenkiana）是天山山区重要的造林树种,为了解天山山区森林上限树木径向生长对气候环境的响应机制,运用树轮气候学方法,通过采自天山东部巴里坤山雪岭云杉林上限的树芯样本建立的树轮宽度标准化年表,采用VS-oscilloscope模型,模拟雪岭云杉的径向生长过程并揭示了过去55 a以来该过程与环境因子的关系。结果表明：（1）模拟得到的树轮宽度指数与实际树轮宽度指数相关系数为0.645（P<0.01）。两者变化趋势具有较好的一致性,表明模型取得了较好的模拟效果。（2）树木径向生长主要限制因子是4~5月和7~8月的土壤湿度,温度是决定树木生长季开始的主要影响因子,而温度决定的生长速率在宽窄轮的形成上并不明显。（3）模拟的树轮宽度指数与生长结束日期的相关系数是-0.413（P <0.01）,说明生长季节的结束日期对树轮宽度的增长有一定的影响。（4）自1984年以来,随着区域气温的逐渐上升,树木生长季的长度有延长的趋势,而树木径向生长却发生衰退现象,1984年以来气温的升高可能是树木生长衰退的主要原因。因而研究从生理角度揭示天山东部森林上限树木径向生长过程中的主要限制因子和限制时段,以期为该区域之后的树轮学研究提供一些借鉴意义。     

Standardization of Qilian Juniper ring-width series in the eastern margin of the Qaidam Basin

Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper (Sabina przewalskii Kom.) tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, i.e. total growth curve (TGC). The samples that contained the complete pith and reached to the growing culmination around the 40th–60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth (IRG) was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology, the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational infor-mation and TGC helps to develop more reliable tree-ring width chronology.     

柴达木盆地东缘祁连圆柏轮宽序列标准化

Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper （Sabina przewalskii Kom.） tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, i.e. total growth curve （TGC）. The samples that contained the complete pith and reached to the growing culmination around the 40th-60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth （IRG） was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology, the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational information and TGC helps to develop more reliable tree-ring width chronology.     

A Reconstruction of Mid–summer Temperatures from Ring–widths of Scots Pine since ad 50 in Northern Fennoscandia

We have reconstructed mid–summer (July) temperatures using a master ring–width chronology of Scots pine ( Pinus sylvestris L.) for northern Fennoscandia, covering nearly the last two millennia. The chronology is constructed from 93 living trees and 275 dead trees collected between 68 ^∘ and 70 ^∘ N, 20 ^∘ and 30 ^∘ E. In standardization, negative exponential functions and, alternatively, regression lines were applied. Because of a strong autocorrelation in the data, we used a model structure including 2–year lagging and a 3–year leading predicter along with the master chronology in the transfer function. Over one–half of the dependent climate variance was retrieved in our final reconstruction model. We indicate the largest temperature anomalies of individual summers as well as longer–term temperature variability starting from ad 50.     

Frequency and variability of missing tree rings along the stems of Pinus halepensis and Pinus pinea from a semiarid site in SE Spain

We studied the occurrence of missing rings (MR) around and along the stems of three Pinus halepensis and three Pinus pinea trees growing in a semiarid Mediterranean site in SE Spain. Tree-ring analyses were performed along 8 radii on stem discs taken at 1 m distances from the base to the top of the trees. The tree rings analysed showed that 19% were missing in P. halepensis and 10% in P. pinea. MR were recorded in 61% of P. halepensis and 24% of P. pinea in the years analysed. Dry conditions from January to May and high late winter to spring temperatures seem to be the main climatic elements promoting MR in both species. In our research into P. halepensis, the frequency of MR gradually decreased from the bottom upward, but no such pattern was observed in P. pinea. Most tree rings were missing only locally (LMR), indicating that wood formation occurred every year in at least some part of a tree, and the tree rings were often discontinuous around and along the stem. Since the frequency of LMR greatly varies around and along the stem, our results suggest that serial sectioning along the stem provides more information on wood formation and responses of trees to environment than studying the samples at breast height only. The disadvantage of the technique is that, as in our study case, research is based on a limited sample size, since it requires destructive sampling with tree felling, which is not usually possible or desirable on highly vulnerable semiarid forest ecosystems.     

油松树轮记录的过去134年伏牛山5-7月平均最高温度

利用豫西伏牛山的两组油松树轮宽度年表,重建了该区域1874年以来5-7月的平均最高温度.并用Jackknife和Bootstrap等方法进行了方程稳定性检验,统计检验参数表明重建序列与实测序列吻合较好,且方程稳定可信,重建方程的解释方差为40%(调整自由度后为39%).重建显示,在过去134年中,豫西伏牛山区5-7月平均最高气温经历了4次冷期和5次暖期.其中,20世纪20-30年代末是最显著的暖期,之后开始降温,至50年代降到谷底,温度小幅回升后,在70-80年代中期又显著下降,80年代末以后开始增温.该重建温度序列与秦岭中部南五台地区温度序列有较好的一致性.     

A DENDROCHRONOLOGICAL METHOD OF STUDYING TREE MORTALITY PATTERNS

This study examines the use of dendrochronological crossdating to determine the dates of death of dead-standing coniferous trees in subalpine forests in the Colorado Rocky Mountains. We cored approximately 800 dead-standing Engelmann spruce (Picea engelmannii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa [Hook.] Nutt.) in two stands and classified them into decay classes. We quantitatively and visually crossdated samples from the dead-standing trees against master chronologies derived from live trees of each species in each stand. The outermost ring on crossdated samples served as an estimate of the year in which a tree died. Seventy percent of the dead-standing trees crossdated successfully. The crossdating technique clearly identified a period of massive mortality of Engelmann spruce attributable to a spruce beetle infestation in the 1940s. This procedure effectively distinguishes between continuous and episodic patterns of tree mortality and compares the relative mortality rates of these coniferous species. Dendrochronological dating of tree deaths is a useful way of providing historical contexts for interpreting tree mortality data derived from short-term monitoring of permanent plots.