中国西南地区川西云杉径向生长与水分利用效率动态变化（英文）

Elevated CO_2 level in the atmosphere is expected to improve the tree growth rates and intrinsic water-use efficiency(i WUE).Although current results inferring from tree rings found the tree growth decline in water-limited area,it is still unclear whether spruce trees in humid southwestern China benefit from the increasing CO_2.In this study,tree-ring width data were used to investigate the tree radial growth rate of Chuanxi spruce(Picea likiangensis var.balfouriana).Moreover,combining with the tree-ring carbon isotope date,we analyzed the physiological responses of Chuanxi spruce to rising CO_2 concentrations in the atmosphere(C_a)associated with climatic change in southwestern China.From 1851 to 2009,i WUE of Chuanxi spruce rose by approximately 30.4%,and the ratio of atmospheric CO_2 to leaf intercellular CO_2 concentration(C_i/C_a)showed no significant trend in the study area.The result suggested that Chuanxi spruce used an active response strategy when C_a was significantly increased.i WUE showed a significant increasing trend in parallel with tree radial growth,indicating that the increasing i WUE resulted in an increase in radial growth.These results suggest that spruce forests in southwestern China have not shown declining trends under increasing C_a and climate change scenarios,in contrast to trees growing in water-limited areas.Therefore,spruce forests benefit from the increasing CO_2 in the atmosphere in the humid areas of southwestern China.     

Radial Growth and Increased Water-Use Efficiency for Ponderosa Pine Trees in Three Regions in the Western United States

We examined changes in and relationships between radial growth and intrinsic water-use efficiency (iWUE) of ponderosa pine (Pinus ponderosa) trees, climate, and atmospheric CO₂ in the western United States since the mid-nineteenth century. We developed tree-ring chronologies for eight sites in three climate regions and used carbon isotope data to calculate pentadal values of iWUE. We examined relationships among radial growth, climate, iWUE, and CO₂ via correlation and regression analyses. Significant upward trends in iWUE occurred at all sites, and despite an absence of climate changes that would favor growth, upward radial growth trends occurred at five sites. Our findings suggest that increased iWUE associated with rising CO₂ can positively impact tree growth rates in the western United States and are thus an evolving component of forest ecosystem processes.     

Dendroecological Analysis of Spruce Budworm Outbreaks and their Relation to Climate Near the Prairie-Forest Border in Northwestern Minnesota

This paper investigates the effects of spruce budworm (Choristoneura fumiferana) on balsam fir (Abies balsamea) and white spruce (Picea glauca) at Itasca State Park in northwestern Minnesota. We studied the species composition, age structure, and radial growth patterns in tree rings along five belt transects at sites infested with spruce budworm. Our objectives were to: (1) discover when the latest spruce budworm outbreak started; (2) determine whether tree growth was similarly reduced in earlier decades, suggesting earlier spruce budworm outbreaks; and (3) test whether radial tree growth and the start of the outbreak(s) were correlated with climate. We used the computer program OUTBREAK to determine that the current spruce budworm infestation began to reduce tree growth in the 1990s, before it was detected by park officials in 2001. The tree-ring record indicated that growth of the host-species trees was periodically reduced at all sites prior to the 1990s. We found no consistent relationship between temperature/precipitation and the initiation of spruce budworm outbreaks, as reconstructed by the OUTBREAK program, at the southwestern edge of the distribution of balsam fir. The Palmer Drought Severity Index, however, was positive (i.e., wetter-than-normal conditions) before increased spruce budworm activity at all sites. Outbreaks are related to climatic conditions, but they also depend on other factors such as the availability of sufficient food for the spruce budworm.     

Growth and physiological responses of larch trees to climate changes deduced from tree-ring widths and δ13C at two forest sites in eastern Siberia

Tree-ring chronologies of ring width and stable carbon isotope ratios (δ¹³C) over the past 160 years were developed using living larch trees at two forest sites, each with different annual precipitation, in eastern Siberia: Spasskaya Pad (SP) (62°14′N, 129°37′E); and Elgeeii (EG) (60°0′N, 133°49′E). Intrinsic water-use efficiency (iWUE) was derived from tree-ring δ¹³C. The physiological responses of the larch trees to climate varied between these sites and over time. Ring widths correlated negatively with summer temperatures at SP, where summer precipitation is lower than at EG, probably due to temperature-induced water stress. Since the 1990s, however, the negative effect of warming has been more severe at EG, where the productivity of larch trees is higher than at SP. A greater reduction of larch tree growth and higher increase rate of iWUE at EG reflects greater temperature-induced water stress, which is incident to the larger forest biomass. Our results suggest that effect of increase in atmospheric CO₂ on larch tree growth is not sufficient to compensate for temperature-induced water stress on larch growth in eastern Siberia and differences in precipitation and forest productivity largely affect the larch tree response to changing climate in eastern Siberia.     

Climatic response of thick leaf spruce (Picea crassifolia) tree-ring width at different elevations over Qilian Mountains, northwestern China

Tree-ring cores of thick leaf spruce (Picea crassifolia) taken from four sites at different elevations, in the middle of the Qilian Mountains, in the arid and semi-arid region of northwestern China, were used to develop four tree-ring width chronologies using standard dendrochronological methods. Results indicate that with increasing altitude the chronologies’ year-to-year variations decreased. Hence, the sensitivity of the tree-ring chronologies to climate decreases with altitude. Further analysis showed that the significant limiting factor on tree growth is spring precipitation. Measurements of stomata density and leaf dry weight suggest the species’ ecological adaptation strategy changes with elevation. At high elevation the metabolic rate of thick leaf spruce decreases, thus showing the effect of the climate.     

Divergent responses of Qinghai spruce (Picea crassifolia) to recent warming along elevational gradients in the central Qilian Mountains,Northwest China

Understanding the radial growth trends of trees and their response to recent warming along elevation gradients is crucial for assessing how forests will be impacted by future climate change. Here, we collected 242 tree-ring cores from five plots across the Qinghai spruce (Picea crassifolia Kom.) forest belt (2600-3350 m a.s.l.) in the central Qilian Mountains, Northwest China, to study trends in the radial growth of trees and their response to climate factors with variable elevation. All the sampled P. crassifolia chronologies showed an increasing trend in the radial growth of trees at higher altitudes (3000-3350 m), whereas the radial growth of trees at lower altitudes (2600-2800 m) has decreased in recent decades. The radial growth of trees was limited by precipitation at lower elevations (L, ML), but mainly by temperature at higher elevation sites (MH, H, TL). Climate warming has caused an unprecedented increase in the radial growth of P. crassifolia at higher elevations. Our results suggest that ongoing climate warming is beneficial to forest ecosystems at high elevations but restricts the growth of forest ecosystems at low elevations.     

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。     

Radial growth rates of two co-occurring coniferous trees in the Northern Rockies during the past century

We examined radial growth rates of locally co-occurring Douglas-fir (PSME – Pseudotsuga menziesii var. glauca) and ponderosa pine (PIPO – Pinus ponderosa var. ponderosa) trees growing within the Northern Rockies to determine if there are differential growth and climatic responses between these species and whether these responses are consistent among topographically and climatologically diverse sites. We developed standardized tree-ring chronologies from seven sites, with each site a matched pair of PSME and PIPO. For each chronology we examined the climate response of radial growth by comparing the standardized ring widths to a suite of climatic variables. We examined temporal changes by comparing 1905–1950 and post-1950 growth rates and climatic conditions. Both conifers experience increased radial growth post-1950. A combination of spring/summer moisture conditions related positively to radial growth and the primary climatic drivers were consistent both between species and within the region. The primary climatic drivers of radial growth remain unchanged during the last century or have trended toward drier conditions unfavorable for growth. We conclude that increases in standardized radial growth rates are unlikely climatically-driven. Other potential vectors of radial growth change, such as atmospheric CO₂ enrichment, have affected these co-occurring species on a largely equal basis and positively.     

大兴安岭北部大白山高山林线动态与气候变化的关系

高山林线植被对气候变化十分敏感,已成为全球变化研究的热点.研究了大兴安岭北部大白山高山林线的树木生长和群落更新动态及其与气候变化、火干扰等因素的关系.结果表明,林线树木的生长对气候变化十分敏感,但其敏感性随着海拔的降低而减弱;在高海拔,林线树木的径向生长与上年生长季后期(8月)降水负相关,而与上年初秋(9月)温度正相关,这限制作用随着海拔的降低而逐渐消失;与此相反,低海拔树木生长与当年冬末春初(3月)的温度负相关,但随着海拔上升这种限制作用消失.分析结果还表明,本地区的群落更新主要受火干扰驱动,而与气候变化没有显著关系.不同树种在火灾后更新的时间存在差异,这种差异又因海拔的不同而异,反映出不同树种的更新策略及对环境变化适应能力的差异.大兴安岭北部的高山林线在树木生长对气候变化的敏感性、与气候因子的关系及群落更新动态等方面均与干旱区林线有明显的差异,这些差异与气候条件、树种、更新驱动力等方面的不同有密切的关系.     

The effect of wood-boring beetles on the radial growth of Prosopis flexuosa DC. in the arid Chaco of Argentina

Traditionally, the effect of wood-boring insects has been related to mechanical damage, which in severe infestations results in breakage of branches and trunks. In contrast, few studies have evaluated the physiological effects of wood-borers on the radial growth of trees. Prosopis flexuosa is the main resource for rural inhabitants in the arid Chaco of Argentina and the cerambycid Torneutes pallidipennis is the principal cause of insect damage in these forests. The presence of annual growth rings in P. flexuosa allowed us to use dendrochronological methods to assess the effect of T. pallidipennis on radial tree growth. P. flexuosa with external infestation symptoms were sampled in Chancaní (Córdoba), central Argentina. Cores from “healthy” and “infested” branches were taken and processed following standard methods in dendrochronology. Generalized Linear Models were applied to compare the growth of healthy and affected tree-ring growth series. Our results showed a growth reduction in branches with cerambycid infestation. These data strongly suggest that the biological cycles of this heartwood-borer affect the growth and normal development of trees, in addition to “mechanical” effects previously proposed. Insects may produce weakening of the host plants and a pronounced reduction in radial tree growth in the most severe cases.     

中国利用树轮资料重建干湿变化研究进展

树木年轮资料定年准确、分辨率高、连续性强,已成为研究过去全球变化的重要信息来源之一。中国树轮与干湿变化研究,样点分布广泛,研究树种较多,重建尺度较长。基于树轮宽度、密度和同位素等各种代用指标,在分析树木径向生长对干湿变化响应、重建历史时期干湿变化等方面取得很大进展。一般来说,在干旱半干旱区的低海拔区域,水分条件,尤其是春季、秋季和年湿润状况,是树木径向生长的重要影响因素。森林上限、相对冷湿区域以及亚热带气候区,树木生长与降水的相关性偏弱。在时间尺度上,基于树轮重建的长于1000年甚至超过2000年的干湿变化序列已有多条,主要分布在青藏高原地区。目前最长年表已达4500年,最长降水序列为3500年。本文通过对部分树轮成果的简要概括,以期为树轮采样和干湿变化重建提供借鉴与帮助。     

Climate Response Analysis of Pinus massoniana Tree-Ring Chronology in Shuangpai County,China

The formation of tree-rings is closely related to climate variation. This paper establishes the tree-ring chronology of Pinus massoniana for a period of 36 years and examines the relationship between the tree-ring chronology and climatic conditions based on tree-ring width samples from three sites on the northeast slopes of Yangming Mountain. This data is used to study the relationship between the tree-ring width of a young tree and climatic conditions in a moist hilly region of southern China and to understand the general pattern of climate variation and its effects on tree growth in the past in this region. The results indicate that changes in tree-ring widths in these sites are closely related to local climatic conditions. There is a significant positive correlation between the radial growth of Pinus massoniana and the mean temperature of the current year from January to May (coefficient of correlation, R, is 0.596, P<0.01) and the mean temperature of the previous year from June to July (R is 0.639, P<0.01). The radial growth of Pinus massoniana is negatively correlated with the total precipitation of the previous year from January to March and November to December (R is -0.46, P<0.05) and negatively correlated with the total precipitation of the previous year from June to July (R is -0.582, P<0.05). The effect of precipitation on the radial growth of Pinus massoniana is known as the “hysteresis effect”.     

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。     

Response of tree-ring growth to climate at treeline ecotones in the Qilian Mountains, northwestern China

Climate constitutes the main limiting factor for tree-ring growth in high-elevation forests, and the relationship between tree-ring growth and climate is complex. Based on tree-ring chronology and meteorological data, the influence of precipitation, mean temperature and mean minimum temperature at yearly, seasonal and monthly scales on the tree-ring growth of Picea crossifolia was studied at treeline ecotones in the Qilian Mountains, northwestern China. The results show that growing season temperatures of previous and current years are important limiting factors on tree-ring growth, particularly June mean temperature and mean minimum temperature of current year. The precipitations in the previous winter and current spring have a positive correlation, and in the current fall has a negative correlation with tree-ring growth, but these correlations are not significant. Our results suggest that temperature controls tree-ring growth more strongly than precipitation at treeline ecotones in the Qilian Mountains.     

祁连山中部树木年轮宽度与气候因子的响应关系及气候重建

研究了祁连山中部不同海拔高度青海云杉的树轮宽度对气候因子的响应,重建了祁连山中部 230 a以来春季3~5月的降水和 170 a以来夏季6~8月的气温序列。结果分析发现,不同高度的云杉树轮生长对春季降水极为敏感,呈现显著正相关;对夏季气温的响应程度,各海拔高度却不相同,夏季气温对上、下限云杉生长有显著影响,但对于森林中部云杉作用并不明显,总体表现为负相关,夏季高温对树木生长不利。气候重建结果发现,祁连山中部的春季230 a以来经历了大幅度长阶段的干湿变化,存在明显的 69 a和 21a周期;170 a以来夏季气温变化频繁,存在明显的2~4a周期。目前,祁连山中部正处于相对干旱和温暖时期,呈现出向暖干方向发展的趋势。     

亚洲热带山地垂直植被带对晚第四纪气候变化的响应

过去一直认为热带低海拔地区晚更新世冰期的地表气温基本维持不变。孢粉分析、树线等研究结果证明,从南半球的新几内亚和赤道附近的苏门达腊,一直到我国的热带山地在末次盛冰期垂直植被带下降了500m～1600m不等。植被带的下降不仅仅与温度变化有关,其他的综合因素如高海拔紫外线辐射、大气CO₂浓度等都可能共同影响垂直植被带的分布。综合研究认为,整个亚洲地区年均温度平均下降约4℃的结果与热带非洲和美洲基本一致,并与近两年来热带海洋表层水温的研究结果和近期的气候模拟结果相吻合。     

Cost Implications of Uncertainty in CO<Subscript>2</Subscript> Storage Resource Estimates: A Review

Carbon capture from stationary sources and geologic storage of carbon dioxide (CO₂) is an important option to include in strategies to mitigate greenhouse gas emissions. However, the potential costs of commercial-scale CO₂ storage are not well constrained, stemming from the inherent uncertainty in storage resource estimates coupled with a lack of detailed estimates of the infrastructure needed to access those resources. Storage resource estimates are highly dependent on storage efficiency values or storage coefficients, which are calculated based on ranges of uncertain geological and physical reservoir parameters. If dynamic factors (such as variability in storage efficiencies, pressure interference, and acceptable injection rates over time), reservoir pressure limitations, boundaries on migration of CO₂, consideration of closed or semi-closed saline reservoir systems, and other possible constraints on the technically accessible CO₂ storage resource (TASR) are accounted for, it is likely that only a fraction of the TASR could be available without incurring significant additional costs. Although storage resource estimates typically assume that any issues with pressure buildup due to CO₂ injection will be mitigated by reservoir pressure management, estimates of the costs of CO₂ storage generally do not include the costs of active pressure management. Production of saline waters (brines) could be essential to increasing the dynamic storage capacity of most reservoirs, but including the costs of this critical method of reservoir pressure management could increase current estimates of the costs of CO₂ storage by two times, or more. Even without considering the implications for reservoir pressure management, geologic uncertainty can significantly impact CO₂ storage capacities and costs, and contribute to uncertainty in carbon capture and storage (CCS) systems. Given the current state of available information and the scarcity of (data from) long-term commercial-scale CO₂ storage projects, decision makers may experience considerable difficulty in ascertaining the realistic potential, the likely costs, and the most beneficial pattern of deployment of CCS as an option to reduce CO₂ concentrations in the atmosphere.     

Climatic response of Picea crassifolia tree-ring parameters and precipitation reconstruction in the western Qilian Mountains, China

Cores of thick leaf spruce from the western Qilian Mountains were subjected to densitometric analysis to obtain data for seven tree-ring parameters (tree-ring width, earlywood width, latewood width, maximum density, minimum density, mean earlywood density and mean latewood density). The chronologies were analyzed individually and then compared with each other. Most of these variables show moderately high values of common variance and mean interseries correlation except latewood and maximum densities. The relationships between the different tree-ring parameters and climate data are also presented. The growth/climate response analyses reveal that the radial growth of thick leaf spruce is the mainly controlled by total annual precipitation (July-June). Herein the residual ring width chronology was used to reconstruct annual (July-June) precipitation of Jiuquan for the period 1768-2009 A.D., and it accounted for 45.0% of the precipitation variance. Multi-taper spectral analysis reveals the existence of significant 11.1-year, 4.9-year, and 2.0- to 3.4-year periods of variability. Spatial analysis shows that the precipitation of Jiuquan has strong common signals for the northern margin of the Tibetan Plateau and Hexi Corridor. Drought events in our reconstruction are compared to the historical archives and other moisture-sensitive tree ring width series in the Hexi Corridor. The results reveal common climatic extremes over much of the Hexi Corridor. Many of these events have had profound impacts on the peoples of the Hexi Corridor over the past several centuries.     

青藏高原东北部与南部地区树木径向生长对气候要素的响应——以祁丰和林周树轮为例

了解树木径向生长对气候响应的区域特征是模拟或预测未来全球变化如何对森林生态系统产生影响的基础。对青藏高原东北部(祁丰)干旱气候条件下与南部(林周)高寒半干旱气候条件下的两条标准化年表分析发现,两年表敏感度均较高,样芯间一致性均较强,为分析树木径向生长对气候要素的响应关系提供了保障。对祁丰和林周树轮宽度序列与其附近酒泉(1951-2009年)和当雄(1963-2009年)气象站上年5月到当年9月的气候因子(月平均气温、月最高气温、月平均最低温和月降水量)进行相关和响应分析发现,祁丰和林周树木的径向生长与当年5-6月平均气温存在负相关关系,相关系数分别为-0.360和-0.466;而与当年5-6月降水量显著正相关,相关系数分别为0.499和0.623。祁丰和林周树轮宽度序列与帕尔默干旱指数(PDSI,1951-2005年)的格网数据在每个月份均呈正相关关系,与5-6月的相关值分别为0.581和0.719。上年7月到当年6月的降水量与祁丰(r=0.529)和林周(r=0.667)树轮宽度序列的相关值也较高,推断干旱状况是限制高原东北部与南部树木径向生长的主要因素。     

东北地区植被分布全球气候变化区域响应

根据东北地区生态气候环境和生物地理规律对Holdridge生命地带分类系统进行修正,将东北地区植被分为寒温带湿润森林、寒温带潮湿森林、温带湿润森林、暖温带湿润森林、温带半湿润森林草甸草原、温带半湿润草甸草原、温带半干旱典型草原、暖温带半湿润草甸草原和暖温带半干旱典型草原等9 个生命地带并分析了其空间分布特征。运用大气环流模式分析东北地区由于温室气体增加导致的气候变化趋势。以此为基础评价东北地区植被分布的区域响应。全球气候变暖情景下,东北地区暖温带和温带范围明显扩大,而寒温带范围缩小甚至退出东北地区,植被分布界限显著北移;同时湿润区面积减少半湿润区和半干旱区扩大,导致森林面积缩小草原面积扩大。