北亚热带生长期温度对马尾松径向生长的影响

近几十年由于温度升高导致的植物生长期的延长已经得到了证实,虽然生长期的长短变化会引起树木生产力变化,但不同起始温度的生长期对树木径向生长的影响尚不明确.为了探索不同起始温度的生长期变化对马尾松生长的影响,找出马尾松生长的敏感温度,本研究选择北亚热带西北边缘汉中地区的老龄马尾松为对象,应用树木年轮学的方法得到了马尾松从1945年到2009年的年轮宽度指数;同时利用汉中气象站的日均温度,计算每一年不同温度的初日、终日、持续时间以及生长期活动积温;分析生长期的变化规律和不同温度生长期对马尾松生长的影响.结果表明:6.0℃-7.5℃的开始时间对年轮宽度有负影响,6.0℃的初日对马尾松的生长最明显,10.5℃的终日时间对生长有显著促进作用;10.0℃和10.5℃的生长期与马尾松生长正相关最为显著,生长期活动积温对生长的影响也较为显著.这些敏感温度分别对应马尾松春季开始萌动、针叶出现以及秋季形成层活动停止时的温度,说明温度的变化导致物候期的变化进而影响植物的年生长量.     

云南轿子山不同海拔急尖长苞冷杉径向生长动态及其低温阈值

环境对树木的功能和生存具有至关重要的意义, 但环境因素影响树木发育的过程仍有待探究。树木径向生长动态监测是深刻了解树木生长状况及其对气候变化响应的重要手段。该研究以云南轿子山不同海拔树线树种急尖长苞冷杉(Abies georgei var. smithii)为研究对象, 对其年内径向生长动态进行监测, 以期明晰树木径向生长各阶段起止时间的海拔差异, 分析不同海拔树木形成层活动和木质部分化对温度的响应, 辨析树木径向生长的低温阈值。结果表明: (1)海拔越高, 径向生长开始的时间越晚, 结束越早, 生长季缩短。海拔每上升100 m, 急尖长苞冷杉径向生长的开始时间推迟4.7 d, 结束时间提前7.2 d, 生长季缩短12.8 d; (2) 3个海拔急尖长苞冷杉的径向生长具有相似的低温阈值(约5 ℃), 温度控制形成层活动的开始与木质部分化的结束; (3)不同海拔急尖长苞冷杉形成层的细胞分裂活动均在温度较高时(夏至日前后)减弱。 形成层活动的结束与海拔引起的温度变化关系较弱, 光周期可能参与了形成层活动结束的调控, 以确保当年新生细胞能够在冻害来临前完成木质化。该研究结果有助于加深树木生长动态对气候变化响应机制的认识, 为更好地适应和应对气候变化提供科学依据。     

年轮和生长轮

木本植物茎的增粗是形成层细胞活动的结果。在四季分明的温带地区,由于季节变化对形成层的影响,通常每年形成一轮年轮。春天气候温和,雨水充沛、植物体生长代谢旺盛,适宜维管形成层活动,细胞的分裂和生长都快,所形成的木质部导管数目较多,腔大壁薄,而木纤维较少,因而这部分木质部质地疏松,颜色较浅,称为早材或春材。秋季,气温渐低,雨水渐少,植物的生长代谢变慢,形成层的活动减弱,生长的情形刚好相反,形成质地坚实致密,颜色较深的晚材,亦称夏材或秋材。裸子     

树轮与交叉定年

树木的生长主要包括径向的生长（长宽）和纵向的生长（长高）。树木的生长除受内部因素的控制外,也受外部环境条件的制约。在具有显著季节变化的温带和寒带地区,树木一般每年都存在周期性的生长变化。春天,紧挨着木质部外面的形成层细胞开始分裂,向内形成木质部细胞,分裂后的细胞大而壁厚,颜色鲜嫩,被称为早材.也叫春材;以后细胞生长减慢,壁更厚,     

水热耦合对沈阳地区油松木质部生长的影响

利用微树芯技术可以从细胞尺度研究树木形成层物候和径向生长的过程,揭示树木生长与气候的关系。油松是我国北方森林的建群树种之一,也是沈阳地区的优势树种。研究2020年整个生长季(4—11月)油松周尺度的形成层及木质部细胞变化,分析油松在沈阳地区的生长规律。结果表明: 油松形成层分裂活动开始于4月初,结束于9月末。木质部从扩大细胞出现(4月中旬)开始生长,到木质化细胞消失(10月下旬)结束,其生长符合“S”型曲线。2020年生长53个/列木质部细胞,最大生长速率(0.55个/列/d)出现在5月末,早晚材细胞于7月末发生转变。在沈阳地区最低温达到0 ℃以上时树木形成层开始活动,影响木质部生长开始和结束的最低临界温度为2～3 ℃。降水在油松整个生长过程中起到促进作用。沈阳地区7月末的高温和水分供给不足是木质部细胞分化形成早晚材的主要因子。     

年轮及假年轮的形成与环境的关系

年轮及假年轮的形成与环境的关系刘宁（北京师范大学生物学系１００８７５）豆什么是年轮当伐倒一株大树或将树干横向锯开,便可以看到一系列的同心圆环,这就是树木的年轮,它是由于形成层周期性活动产生的。每一个圆环是一个年轮,由早材和晚材构成,代表着形成层在一个...     

帽儿山地区兴安落叶松人工林树木年轮气候学研究

通过帽儿山兴安落叶松（Larix gmelinii）人工林树木年轮样本和气象资料,对该地区兴安落叶松进行了树木年轮气候学研究,结果表明：过去50年年均温度上升达到了显著水平（p<0.05）,平均温度每10年约上升0.4℃,年平均最高气温每10年约上升0.3℃,年平均最低气温每10年约上升0.5℃,但是年降水量随着年份变化不显著（p>0.05）。从月均温度来看,所有月份均出现明显上升趋势,其中冬季2月份温度上升最为明显,达到0.9~1℃/10年,而夏季（6~8月）上升的较小,达到0.2~0.7℃/10年;多数月份降雨量随年龄变化不显著（p>0.05）。在这一气候变暖过程中,早材及总年轮宽度生长随着夏季（6~7月）温度上升而下降,春季(5月)温度的升高而升高,晚材随着秋季（9月）温度上升而增加,导致在年水平上,年轮生长随着年均温的变化不显著（p>0.05）。降雨量在未来气候变化过程中,没有稳定的变化趋势,但是对年轮影响明显,在年水平上,早材与年轮的生长均受降水量的影响较大(p<0.05)。如果未来东北地区气候变暖趋势明显,而降水量变化不明显,春季和秋季温度升高导致的年轮生长增加会被夏季过高温度抑制年轮生长所抵消,因此,落叶松林径向生长受到的影响可能不大。     

太行山南麓不同径级栓皮栎生长对气候要素及干旱事件的响应

为评估径级对树木的气候-生长关系的影响,建立太行山南麓低海拔地区栓皮栎全轮、早材、晚材宽度年表,对比两个径级栓皮栎人工林径向生长对气候响应的敏感性差异,使用叠加时代分析揭示干旱事件对不同径级栓皮栎的影响,为气候变化背景下研究区栓皮栎人工林可持续经营提供参考数据。结果表明: 大径级栓皮栎全轮、晚材年表的平均敏感度高于小径级栓皮栎年表,但小径级栓皮栎早材年表的平均敏感度高于大径级栓皮栎早材年表。晚材是树轮气候响应最敏感的组分。两径级栓皮栎标准年表指数对当年气候因子的响应模式相似。小径级栓皮栎全轮、晚材生长对当年6—8月的气候因子更敏感,其早材对生长季之前(1—2月)气候因子更敏感;而大径级栓皮栎早材对去年的气候因子更敏感,有更强的滞后效应。研究区栓皮栎对干旱非常敏感,干旱年份两径级栓皮栎全轮、晚材的径向生长量显著低于上一年,且大径级栓皮栎的减少幅度更高,但干旱后大径级栓皮栎生长恢复程度更高。     

河北木兰围场油松年轮生态学的初步研究

运用树木年轮气候学方法,研究了河北木兰围场油松的生长与气候要素之间的关系.结果表明：油松生长对环境变化十分敏感,以早材最为敏感.5、6月气温与油松生长存在显著的负相关关系;6月的降水和相对湿度对油松早材的生长有促进作用, 上年9月到翌年9月的降水对油松生长有更强的促进作用;12月到翌年3月的相对湿度对油松晚材生长的促进作用较干旱和全轮显著;油松的生长与大尺度气候波动存在一定的相关性.1951—2006年间,围场地区增温明显.随气温的升高,油松生长对温度和降水的敏感性下降,且有向相反方向转变的趋势.百年尺度上5—6月平均气温的重建值与观测值差异较大,说明当地油松的宽度生长对气候因子变化的敏感性波动较大.     

气候变暖下大兴安岭落叶松径向生长对温度的响应

大兴安岭是我国气候变暖的敏感地区。为比较在升温过程中不同地区落叶松(Larix gmelinii)径向生长对温度的响应差异,在大兴安岭主脉南段、中段和北段进行树木年轮取样,建立了各点年轮宽度年表,根据年表第一主成分载荷系数分类最终合成南部、中部和北部各区年轮指数。利用相关函数分析了落叶松径向生长与温度变化的关系,结合主成分分析对比了不同地区树木年轮宽度变化对温度的响应差异。结果表明:落叶松径向生长对温度变化的响应呈现明显的南北差异(中部北部南部);南部年轮指数与上年11月到当年4月的平均温度显著相关,中部年轮指数与上年生长季(6–8月)和当年3–10月的平均温度显著负相关,北部年轮指数与生长季前(4–5月)的平均温度极显著正相关。气候变暖背景下,高温引起的区域暖干化使土壤水分成为限制落叶松径向生长的主要因子,土壤干旱程度加剧使落叶松生长对温度变化的响应增强。胸高断面积增量指示的落叶松生产力经历了从响应低温胁迫到响应高温引起的水分胁迫的转变。未来几十年,若温度持续升高,大兴安岭地区落叶松径向生长量将呈南部和中部降低、北部升高的趋势。     

Tree-rings to climate relationships in nineteen provenances of four black pines sub-species (Pinus nigra Arn.) growing in a common garden from Northwest Tunisia

In the Mediterranean region, the effects of climate change on tree growth have been more and more noticeable in recent decades. Pinus nigra is one of the most common mid-elevation pine in this region and one of the species most affected by increasing dryness. In Tunisia, in order to guide species selection for future reforestation of the Khroumirie Mountains, research studies are under way to improve knowledge of black pine ecology. The effects of interannual climate variations on radial growth were compared for 19 provenances of black pine in a 51-year-old common garden experiment in Souiniet (NW Tunisia, 492m) in a humid Mediterranean bioclimate. A significant positive correlation with April precipitation and a significant negative correlation with spring temperature were noted. A cool wet spring is beneficial to growth as it affects tree water balance at the onset of the growing season; in contrast, spring drought is responsible for low annual growth. Mild January–February temperatures have a positive influence on ring width as mild winters may foster photosynthesis and promote early resumption of cambial activity. Analysis of the pointer years showed that winter snow and hail are major factors limiting growth of black pine in the studied area. Despite overall similarities in ring width to climate relationships among provenances, differences observed attest to the interaction of the environment and genetic control of black pine diameter growth.     

柴达木盆地东缘青海云杉树轮细胞结构变化特征及其对气候的指示

基于青海柴达木盆地东缘山地青海云杉生长上限的树轮样本,在获取树轮宽度数据的同时,获取了细胞特征指标,包括细胞个数和细胞大小,建立了树轮早材、晚材、整轮的细胞个数标准年表和细胞大小的最大值、最小值年表,并通过与附近茶卡气象站过去31年（1970—2000年）逐月降水量和温度的相关分析和响应函数分析,从细胞尺度探讨了青海云杉生长与外界气候要素的关系.结果表明：早材细胞个数与冬半年（上年10月至当年3月）温度之间呈正相关关系;晚材细胞个数除了与11月和12月最低温度呈显著正相关外,还与生长季中7月和8月平均温度呈显著相关关系;早、晚材细胞个数同时与7月的降水量呈显著负相关.早材细胞个数与5月的降水量呈正相关关系.对于早材最大细胞大小的年表来说,其变化与2月的降水量变化有很好的一致性,而晚材最小细胞的大小与8月降水量的变化同步.细胞个数和细胞大小不仅记录了树轮宽度所记录的温度变化信息,还额外记录了一定的降水信息,说明不同的树木生长指标能够记录不同的气候信息.利用同一地点同一树种不同类型的树轮指标,能够提取多种气候要素的变化信息,这对将来从同一样点的树轮资料中提取更丰富的气候信息以及发掘树轮气候学的潜力具有一定意义.     

The climatic drivers of primary Picea forest growth along the Carpathian arc are changing under rising temperatures

Climatic constraints on tree growth mediate an important link between terrestrial and atmospheric carbon pools. Tree rings provide valuable information on climate‐driven growth patterns, but existing data tend to be biased toward older trees on climatically extreme sites. Understanding climate change responses of biogeographic regions requires data that integrate spatial variability in growing conditions and forest structure. We analyzed both temporal (c. 1901–2010) and spatial variation in radial growth patterns in 9,876 trees from fragments of primary Picea abies forests spanning the latitudinal and altitudinal extent of the Carpathian arc. Growth was positively correlated with summer temperatures and spring moisture availability throughout the entire region. However, important seasonal variation in climate responses occurred along geospatial gradients. At northern sites, winter precipitation and October temperatures of the year preceding ring formation were positively correlated with ring width. In contrast, trees at the southern extent of the Carpathians responded negatively to warm and dry conditions in autumn of the year preceding ring formation. An assessment of regional synchronization in radial growth variability showed temporal fluctuations throughout the 20th century linked to the onset of moisture limitation in southern landscapes. Since the beginning of the study period, differences between high and low elevations in the temperature sensitivity of tree growth generally declined, while moisture sensitivity increased at lower elevations. Growth trend analyses demonstrated changes in absolute tree growth rates linked to climatic change, with basal area increments in northern landscapes and lower altitudes responding positively to recent warming. Tree growth has predominantly increased with rising temperatures in the Carpathians, accompanied by early indicators that portions of the mountain range are transitioning from temperature to moisture limitation. Continued warming will alleviate large‐scale temperature constraints on tree growth, giving increasing weight to local drivers that are more challenging to predict.     

Climate–tree growth relationships of longleaf pine (Pinus palustris Mill.) in the Southeastern Coastal Plain, USA

Knowledge of tree growth/climate response relationships is important to dendroecological studies and dendroclimatic reconstructions, particularly in the Southeastern Coastal Plain where few such studies have been attempted. To this end, we developed tree-ring chronologies of total ring width, earlywood width, and latewood width from longleaf pine (Pinus palustris Mill.) at three sites in the Southeastern Coastal Plain to examine the climate–growth relationships for this tree species. The length of these chronologies is unprecedented for southern pine chronologies in the Southeast. We compared the tree-ring chronologies to monthly temperature, precipitation, Palmer drought severity index (PDSI), and Palmer hydrological drought index (PHDI) data from the pertinent climate divisions. We found that PDSI and PHDI have the highest correlation with longleaf pine growth, and the strongest relationships between longleaf pine growth and these variables occur between July and November. Precipitation in the spring and summer was also positively related to growth at all sites. The relationship between temperature and growth was the weakest among all climate variables, but warm summer temperatures had a consistent, negative relationship with longleaf pine growth. The climate signal in the latewood was generally more robust than for total ring width and earlywood width.     

沈阳福陵油松年轮对全球性气温波动的响应

研究了沈阳福陵油松年轮宽度变化与沈阳地区以气温为主的气候因子和1880年以来的全球气温、全球陆地和海洋温度以及北半球气温等温度变化的关系.结果表明:沈阳油松年轮宽度与全球气温变化、全球陆地和海洋温度变化和北半球气温变化有一定的相关性,而且3个大空间尺度的温度波动和沈阳当地气温对油松年轮宽度的影响较一致:冬季12、1月的气温和春季4、5月的气温对油松生长影响显著(P<0.05).油松年轮宽度和3个大尺度温度序列存在3～8年公共准周期变化,其19.3年和23.2年准周期可与3个大尺度温度变化均含有的20.8年的准周期对应.说明沈阳油松年轮宽度与不同尺度的温度波动呈正相关,升温变化在过去大部分时期对沈阳油松年轮生长存在积极的影响.     

北京东灵山辽东栎林树木生长对气候要素的响应特征

根据北京东灵山辽东栎(Quercus wutaishanica)的年轮宽度资料,分析了该地区树木生长在1951—2010年时段对气候要素的响应特征。相关分析表明,夏季干旱胁迫是限制东灵山辽东栎树木生长的最为重要的气候要素,主要体现在与夏季(7—9月)温度的负相关关系和夏季降雨(7月)的正相关关系,另外春季(5月)温度对树木生长也有一定的限制性影响;年表与生长季节干旱指数普遍呈正相关关系,进一步证实了干旱胁迫对树木生长的限制性作用。滑动相关分析表明,年表与夏季温度负相关关系及与夏季降雨的正相关关系在近期趋于增强,这表明夏季干旱胁迫对树木生长影响作用有不断加强的趋势。辽东栎林是北京东灵山温带落叶阔叶林的优势群落,在暖干化气候不断发展背景下,辽东栎林生长的干旱胁迫效应将更加突出,对北京东灵山地区森林的生产力及固碳能力产生负面影响。     

长白山北坡不同年龄红松年表及其对气候的响应

运用树木年轮气候学方法,研究了长白山北坡红松(Pinus koraiensis)不同年龄年表特征及其与气候因子间的关系,以期揭示年龄因素对年表的潜在影响。结果表明,平均年龄为63a的红松低龄年表与平均年龄为184a的高龄年表对气候的响应明显不同:低龄红松径向生长与当年1、2月月平均温度负相关(P<0.05),同时也受到上年及当年多个月份的月平均最高温度或最低温度的影响,但与降水的相关性未达到显著水平;高龄红松径向生长则与月平均温度间的关系不明显,而与当年1、2、4、6、7、9月的月平均最高温度正相关,与当年4月、9月的月平均最低温度负相关,同时受到上年5月及当年5月月总降水量的影响。因此,年龄因素对红松年表的气候响应方面存在一定影响,且高龄年表对气候响应的敏感性更高,包含有更多的气候信息。     

Environmental controls and patterns of cumulative radial increment of evergreen tree species in montane,temperate rainforests of Chiloé Island,southern Chile

We investigated the local environmental controls on daily fluctuations of cumulative radial increment and cambial hydration of three dominant, evergreen tree species from montane, Coastal rainforests of Chiloé Island, Chile (42° 22′ S). During 2 years (1997–1998 and 1998–1999) we recorded hourly cumulative radial increments using electronic band dendrometers in the long‐lived conifer Fitzroya cupressoides (Cupressaceae), the evergreen broad‐leaved Nothofagus nitida (Nothofagaceae), and the narrow‐leaved conifer Podocarpus nubigena (Podocarpaceae). We also measured soil and cambial tissue hydration using capacitance sensors, together with air and soil temperature and rainfall during the period of the study. In addition, we collected cores of these tree species to evaluate how dendrometer measurements reflect annual tree ring width. One‐year long daily time series of cumulative radial increments suggests that radial growth of Fitzroya cupressoides was initiated slowly in early spring, with a maximum in early summer. Multiple regressions showed positive relations between daily precipitation and radial index (i.e. the difference in cumulative radial increment of two consecutive days) in the three species. According to path analysis there was a significant direct effect of changes in tree hydration on radial index of the three focal species. In emergent, pioneer species such as Nothofagus and Fitzroya, radial index was negatively affected by changes in maximum air temperature and photosynthetically active radiation, probably because of high evapotranspiration demand on warm sunny days. The shade‐tolerant species Podocarpus nubigena was positively affected by photosynthetically active radiation. Our diel scale findings support the use of tree ring widths for reconstructing past climate in these southern temperate forests and provide evidence that rainforest trees may be highly sensitive to future declines in rainfall and temperature increases during summer.