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1.
根据黄土高原南北样带尺度的人工刺槐林(Robinia pseudoacacia)的年轮宽度资料,分析了该地区刺槐树木生长趋势,以及刺槐年表对气候响应随降雨梯度变化规律。研究结果表明延安以北的刺槐样点(绥德、神木)年轮指数近期趋于下降,树木有生长衰退现象;而延安以南刺槐样点(延安、富县、宜君、永寿)年轮指数近期趋于上升,树木无生长衰退现象。气候响应结果表明,刺槐年表对气候响应均以延安样点最为敏感,表现年表与温度的负相关关系,以及年表与降雨和干旱指数的正相关关系,而延安以北和以南刺槐样点对气候响应敏感性均较低。黄土高原中部延安地区地处森林草原过渡带,刺槐生长对外界环境变化最为敏感,年表中气候信号也较强;延安以南地区地处森林植被带,气候条件较为适宜刺槐林生长,因而年表中气候信号较弱;延安以北地区地处草原植被带,气候条件比较恶劣,刺槐生长对干旱气候已有一定适应性特征,因而年表中气候信号也较弱。  相似文献   

2.
While the forest-tundra zone in Siberia, Russia has been dendroclimatologically well-studied in recent decades, much less emphasis has been given to a wide belt of northern taiga larch forests located to the south. In this study, climate and local site conditions are explored to trace their influence on radial growth of Gmelin larch (Larix gmelinii (Rupr.) Rupr.) trees developed on permafrost soils in the northern taiga. Three dendrochronological sites characterized by great differences in thermo-hydrological regime of soils were established along a short (ca. 100 m long) transect: on a river bank (RB), at riparian zone of a stream (RZ) and on a terrace (TER). Comparative analysis of the rate and year-to-year dynamics of tree radial growth among sites revealed considerable difference in both raw and standardized tree-ring width (TRW) chronologies obtained for the RZ site, characterized by shallow soil active layer depth and saturated soils. Results of dendroclimatic analysis indicated that tree-ring growth at all the sites is mostly defined by climatic conditions of a previous year and precipitation has stronger effect on TRW chronologies in comparison to the air temperatures. Remarkably, a great difference in the climatic response of TRW chronologies has been obtained for trees growing within a very short distance from each other. The positive relation of tree-ring growth with precipitation, and negative to temperature was observed in the dry site RB. In contrary, precipitation negatively and temperature positively influenced tree radial growth of larch at the water saturated RZ. Thus, a complicate response of northern Siberian larch forest productivity to the possible climate changes is expected due to great mosaic of site conditions and variability of environmental factors controlling tree-ring growth at different sites. Our study demonstrates the new possibilities for the future dendroclimatic research in the region, as various climatic parameters can be reconstructed from tree-ring chronologies obtained for different sites.  相似文献   

3.
为明确黄土高原丘陵区第三副区典型流域-甘肃天水罗玉沟流域刺槐生长过程及其与气候关系随海拔变化的规律。利用树木年代学方法分别建立高、中、低3个海拔刺槐的标准年表,并分析不同海拔刺槐径向生长过程以及对气候变化的响应。研究结果表明:(1)中、低海拔刺槐径向生长与温度因素多为负相关,而高海拔刺槐径向生长与温度因素多呈正相关。高海拔刺槐生长与上一年生长季(6月)、休眠期(当年3—4月)和当年生长季(6月)均温、最低温和最高温呈显著正相关,其中受最低温影响最显著;中、低海拔刺槐与上一年生长季和当年生长季的均温、最高温和最低温呈显著负相关,低海拔受均温影响显著。(2)随海拔升高,刺槐径向生长与降水和相对湿度的正相关呈降低趋势。低海拔刺槐生长与上一年生长季(7—9月)和当年生长季(6—9月)降水、相对湿度呈显著正相关,中海拔刺槐与当年生长季(6—9月)降水、相对湿度呈显著正相关,而高海拔刺槐生长与上一年生长季(6—7月)相对湿度呈显著负相关。(3)低海拔刺槐与上一年6月—当年10月帕默尔干旱指数(PDSI)呈显著正相关;中海拔刺槐与上一年6月和当年2—10月PDSI呈显著正相关;高海拔刺槐与上一年6—...  相似文献   

4.
全球气候变化导致的区域森林生长衰退和死亡普遍发生,并对森林生态系统结构和组成以及主要生态系统服务功能产生重要影响,然而相关研究在国内还显偏少。根据黄土高原延安羊圈沟小流域人工刺槐林健康和衰退个体分别构建了刺槐健康和衰退树轮年表,并对人工刺槐林健康和衰退年表特征及对气候响应敏感性进行了对比分析。结果表明刺槐衰退年表质量较低,其年表统计参量,包括平均敏感度、样芯间相关系数、信噪比和样本群体代表系数均要低于刺槐健康年表。刺槐衰退年表在生活史早期(1985-2007年)与生长健康年表的波动趋势相类似,而在生活史晚期(2008-2016年)与健康年表指数出现生长分离现象,生长速率明显偏低。年表与气候要素响应分析表明刺槐生长衰退年表对气候要素响应敏感性要低于刺槐生长健康年表,但是两者均含有干旱胁迫气候信号,主要体现在与温度呈负相关关系,与降雨和干旱指数的正相关关系。年表与极端气候年份的时序叠加分析表明,生长健康和衰退年表对极端干旱年份响应敏感性均较高,表明极端干旱胁迫条件对刺槐生长健康和衰退个体均有抑制性影响;生长健康年表对极端湿润年份响应敏感性明显高于衰退年表,表明刺槐健康个体比衰退个体更能有效利用湿润年份有利条件,而具有较高的生长速率。研究揭示出黄土高原健康和衰退刺槐个体生长趋势变化及对气候响应敏感性均存在明显差异性,将为气候变化背景下人工刺槐林生长衰退和死亡预测模型建立提供科学依据,因而对黄土高原人工刺槐林生态恢复和保护及可持续经营具有科学价值。  相似文献   

5.
We propose a technique for separating the climatic signal which is contained in two tree-ring parameters widely used in dendroclimatology. The method is based on the removal of the relationship between tree-ring width (TRW) and maximum latewood density (MXD) observed for narrow tree rings from high latitudes. The new technique is tested on data from three larch stands located along the northern timberline in Eurasia. Correlations were calculated between the temperatures of pentads (five consecutive days), TRW chronologies and MXD chronologies calculated according to the standard and proposed methods. The analysis confirms the great importance of summer temperature for tree radial growth and tree-ring formation. TRW is positively correlated with the temperature of four to eight pentads (depending on the region) at the beginning of the growth season, but MXD as obtained by the standard technique is correlated with temperature over a much longer period. For maximum density series from which the relationship between MXD and TRW has been removed (MXD′), there is a clear correlation with temperatures in the second part of the growing season. These results are consistent with the known dynamics of tree-ring growth in high latitudes and mechanisms of tree-ring formation.  相似文献   

6.
Since the late-19th century, the Middle Volga has played a major role in the supplying grains and other agricultural products to European Russia. The study area is located in the south of sub-boreal forest in the north and in the forest-steppe in the south. Due to large seasonal differences in rainfall, agriculture in the region, especially in its southern part, strongly depends on hydroclimate variability. According to climate model forecasts, the frequency and intensity of droughts in the Middle Volga are expected to increase due to ongoing warming. Here we introduce 16 new Scots pine tree ring width (TRW) chronologies (Pinus sylvestris L.) from the region and use a dendroclimatological approach to determine what climatic factors drive radial growth. Our analysis revealed contrasting climate signals across the network of sites with chronologies from the north showing weak correlation with May temperature and precipitation (r = −0.27 and r = 0.28, respectively), while the southern sites demonstrated stronger relationships with climate in the first half of the vegetation season (May to July temperature, r = −0.26 to −0.43; May and July precipitation, r = 0.29–0.35). The northern sites did not demonstrate a strong growth response to the self-calibrated Palmer drought severity index (scPDSI) whereas the southern group was more drought sensitive had a strong drought response and positively correlates with scPDSI for the period from previous July to the current October (r = 0.27–0.56). Based on this strong relationship between southern TRW and scPDSI we reconstruct June-September scPDSI using the most sensitive sites (T04S, T06S, T08S) for the period from 1830 to 2014. The model explains 31% of variance. Our reconstruction shows droughts in 19th century: in 1831–33, 1851, 1853, 1859, 1863–65, 1880, 1891–92, 1897–98 and in 20–21th centuries: in 1906, 1921, 1936, 1939, 1967, 1975, 1996, 2010.  相似文献   

7.
运用树木年代学的原理和方法,对普达措国家公园大果红杉、长苞冷杉、高山松和麦吊云杉4个优势针叶树种的年轮宽度进行测量,建立年轮宽度差值年表。分析年表与香格里拉气象站的日、月气候数据的相关性,研究4个优势针叶树种的径向生长对气候因子的响应。结果表明: 大果红杉的年生长速率最高,长苞冷杉的年生长速率最低;4种针叶树径向生长对气候因子的响应存在物种特异性,大果红杉与气候因子的相关性最强,麦吊云杉的径向生长对气候因子的响应不敏感;长苞冷杉树轮宽度年表与上年冬季(11、12月)和当年夏季(7月)的平均温度呈显著正相关;大果红杉树轮宽度年表与生长季早期(6月)温度呈显著正相关,与同期降水量和相对湿度呈显著负相关;而高山松树轮宽度年表与生长季早期(5月)的降水量和相对湿度呈显著正相关,与同期最高温度呈显著负相关,表明高山松的径向生长主要受生长季早期水分可利用性的影响。  相似文献   

8.
9.
Clanwilliam cedar (Widdringtonia cedarbergensis; WICE), a long-lived conifer with distinct tree rings in Cape Province, South Africa, has potential to provide a unique high-resolution climate proxy for southern Africa. However, the climate signal in WICE tree-ring width (TRW) is weak and the dendroclimatic potential of other WICE tree-ring parameters therefore needs to be explored. Here, we investigate the climatic signal in various tree-ring parameters, including TRW, Minimum Density (MND), Maximum Latewood Density (MXD), Maximum Latewood Blue Intensity (MXBI), and stable carbon and oxygen isotopes (δ18O and δ13C) measured in WICE samples collected in 1978. MND was negatively influenced by early spring (October-November) precipitation whereas TRW was positively influenced by spring November-December precipitation. MXD was negatively influenced by autumn (April-May) temperature whereas MXBI was not influenced by temperature. Both MXD and MXBI were negatively influenced by January-March and January-May precipitation respectively. We did not find a significant climate signal in either of the stable isotope time series, which were measured on a limited number of samples. WICE can live to be at least 356 years old and the current TRW chronology extends back to 1564 CE. The development of full-length chronologies of alternative tree-ring parameters, particularly MND, would allow for an annually resolved, multi-century spring precipitation reconstruction for this region in southern Africa, where vulnerability to future climate change is high.  相似文献   

10.
《Dendrochronologia》2014,32(3):237-244
The long-term radial growth responses to drought and climatic variability of less-studied species such as Abies borisii-regis (Mattf.) remain poorly understood.We tested the hypothesis that severe short-term drought conditions during summer months will impact the radial growth of A. borisii-regis (Mattf.) trees and such impact will have a more pronounced effect on latewood (LW) than earlywood (EW) width.Correlation analysis was employed to investigate the impact of climatic drivers (temperature, precipitation) and drought, using the Standardized Precipitation Evapotranspiration Index (SPEI) calculated at cumulative time scales (1–12 months), on EW, LW and tree-ring width (TRW) in A. borisii-regis (Mattf.) trees from South-Eastern Albania.We found that EW width was positively correlated with precipitation in July and previous September, while the LW width and TRW was enhanced by the current June–July precipitation. Previous autumn and current summer high temperatures constrained the radial growth in A. borisii-regis (Mattf.) trees, particularly the LW and TRW. All the tree-ring widths components showed the highest significant response to drought at short cumulative time scales (<4 months) mainly during July, August and September. The highest impact of drought was observed for the LW width.Under a future reduction of summer precipitation and temperature increase, the A. borisii-regis (Mattf.) may show a decrease in EW formation, causing a decline of radial growth, leading to a reduction in hydraulic conductivity and carbon uptake in these forests.  相似文献   

11.
The plasticity of climate-growth relationships of trees is one of the main factors determining the climate-induced changes in forest productivity and composition. In this study, high-frequency variation of tree-ring width (TRW) of four native and three alien tree species and two hybrids of Populus L. growing in Latvia (hemiboreal zone) was compared using a principal component analysis based on TRW indices for the period 1965–2009. The effect of climatic factors was assessed using a bootstrapped correlation analysis. Influence of common climatic factors related to the length of the vegetation season, winter temperature, and water regime in summer was traced in the TRW of the studied species and hybrids. The combination and effect of the identified factors differed by species (and hybrids), to a certain extent explaining the diversity of TRW patterns. Nevertheless, some similarities among the species were also observed, suggesting the plasticity of growth response. Scots pine was generally sensitive to winter temperatures, but Norway spruce was mainly sensitive to summer water regime, while black alder was sensitive to winter temperatures and precipitation in spring. In contrast, silver birch showed the lowest sensitivity to the tested climatic factors (demonstrating sensitivity to winter precipitation in a few sites), suggesting tolerance to weather fluctuations. The TRW of the alien species was primarily sensitive to climatic factors related to water regime in the summer of the year preceding the formation of tree-ring, implying differences in mechanisms regulating wood increment. Nevertheless, temperature in the dormant period was significant for European larch in a few sites, suggesting sensitivity to cold damage. The variation of TRW of Populus hybrids diverged from others, as their growth was negatively correlated with the temperature in autumn, spring, and summer and positively correlated with water balance. Although the annual water balance in Latvia is positive, the effect of water deficit on tree growth was apparent.  相似文献   

12.
基于树轮年代学手段,建立了岷江冷杉和方枝柏树轮宽度标准年表以及混合树种年表,研究川西地区理县凉台沟两种针叶树种径向生长对气候变化的响应,为全球变暖背景下该地区森林生态系统的保护与管理提供依据。结果表明:混合年表中包含了2个单个年表的共同气候信息,其信噪比和样本总体解释量均高于单个年表。与气候因子的相关分析显示,3个年表对气候要素的响应表现出较好的一致性,均对温度响应敏感,尤其是方枝柏最为敏感。相对湿度在5、10月对两树种的限制作用明显强于降水。1994年升温突变后,岷江冷杉宽度年表与月均温的相关性变化最为明显,部分月份由负相关转变为正相关,表明岷江冷杉树木径向生长对温度的响应呈现出不稳定性,但两树种径向生长呈差异性变宽趋势,对气温响应的敏感性减弱。  相似文献   

13.
张文涛  江源  王明昌  张凌楠  董满宇 《生态学报》2015,35(19):6481-6488
为研究树木生长对气候变化的响应状况,选取芦芽山阳坡的3个海拔高度建立了华北落叶松(Larix principis-rupprechtii)的树轮宽度年表。年表的统计参数表明,3条年表均为研究气候信息的可靠资料。结果表明,芦芽山阳坡华北落叶松的径向生长和生长与气候的关系均具有海拔差异,中海拔(2440 m)和高海拔(2540 m)的华北落叶松具有相似年际生长变化,而二者均与低海拔(2330 m)华北落叶松的年际生长不同。低海拔华北落叶松的生长与4月平均气温和上一年11月降水量显著负相关,而中海拔和高海拔的生长均与上一年10月平均气温和6月降水量显著负相关。通过年表与气候因子之间的滑动相关分析发现,3个海拔高度华北落叶松生长与气候因子的关系均不稳定,生长与气温条件之间的显著相关关系是随着气温升高而出现的。气温的升高引起了华北落叶松生长与气温因子关系的海拔差异,以及径向生长的海拔差异。这一结果对于气候变化对植被垂直梯度影响的研究具有一定参考价值。  相似文献   

14.
Searching for a robust tree-ring parameter useful for paleoclimatic purposes is one of the most demanding topics in the modern paleoscience. Since Blue Intensity has already expressed itself in different geographical locations all over the world as a possible replacement for maximum density, close attention is paid to investigate features of the inferred signal. The Solovki Islands is a unique location in Northern Russia where two important factors that make this territory attractive for developing a long tree-ring chronology have been met: modern long-living trees and building activities using old trees that were started by monks in the middle of the 16th century. The main goal of the research is to develop pine and spruce chronologies based on tree-ring width (TRW) and delta Blue Intensity (dBI) and to assess the ability of these parameters to be used as climate predictors. As a result, 14 conifer chronologies from 7 sites (4 for pine and 3 for spruce) were developed. The composite pine and spruce chronologies span a period of 474 and 378 years each. Cross-correlation of dBI-based chronologies of both conifers is high (r = up to 0.71 while for TRW-based chronologies it is lower on average (−0.18 to 0.63). Intra-species correlation of TRW chronologies in some cases achieved even negative values (r = −0.18. Discrepancies found between TRW chronologies of pine and spruce could be explained by differences in climatic signals. Response function analysis with monthly temperatures revealed that growth of pine depends on the previous August, while spruce has a temporally stable and strong relation to June temperatures. Compared to TRW, dBI-based chronologies have a high correlation with summer temperatures (r = 0.64 and 0.66 for spruce and pine, respectively). Presented research points out the importance of the response function analysis suggesting that depending on goals of the study several tree-ring parameters could be used, e.g., tree-ring width of spruce responses to June temperatures, while dBI to the whole summer.  相似文献   

15.
Pinus Massoniana is the most widely distributed coniferous species in southern China and one of the most distributed species for plantation in China. It is not uncertain about the responses of tree growth to the combined effects of regional drying and the increase in the intrinsic water-use efficiency (iWUE) due to increased atmospheric CO2. This study addressed this issue by comparing the tree growth patterns as represented by three tree-ring width chronologies with climate variables and three iWUE series derived from three tree-ring stable carbon isotope discrimination chronologies (Δ13C) from Pinus Massoniana in Daiyun Mountain, central Fujian province of China. Among these chronologies, we reported the first tree-ring carbon isotope discrimination chronologies (Δ13C) from Fuzhou area spanning last 210 years. It was found that tree radial growth is mainly limited by dry condition from May to October. Growth limitation by cold condition was only found in one high altitude site (780m) in early spring and late autumn. The tree-ring carbon discrimination was enhanced under conditions with low relative humidity and sufficient sunshine in late summer and autumn. In general, the iWUE showed a significantly increasing trend since the 1850s for all the sites in response to the increase in atmospheric CO2. However, the growth promotion of the increased iWUE on tree growth could not compensate the growth limitation caused by drought. Especially since the 1960s, a growth decline was found at two drought stressed sites at low altitudes. On the other hand, the increase in temperature of spring and autumn and iWUE has most likely enhanced tree growth at the high altitude site.  相似文献   

16.
刺槐是广泛分布于黄土高原的典型水土保持植物。以黄土丘陵区甘肃天水吕二沟小流域为研究区,分析了刺槐径向生长过程及其对气候因子的响应,并开展了利用刺槐年轮估算小流域年径流量、年输沙量的适用性评估。研究表明:(1)吕二沟刺槐人工林的径向生长随林龄呈明显的下降趋势,在幼龄林阶段(1—10 a)刺槐处于快速径向生长期((4.17±0.74)mm/a),之后逐渐下降,中龄林、成熟林、过熟林阶段(11—40 a)平均生长速率为(2.31±0.41)mm/a,较前期下降了44.60%。刺槐胸高断面积增量(BAI)在1—10 a平均以(5.46±2.13)cm2/a的速度生长,在11—40 a仍保持上升趋势但年际间生长波动较大,生长速率平均为(10.80±1.95)cm2/a,流域刺槐生长并未发生明显衰退。(2)刺槐的径向生长与温度多呈负相关,与降水、相对湿度及帕默尔干旱指数(PDSI)多呈正相关。其中刺槐径向生长与上年8月、9月(P<0.05)及当年7月均温、最高温呈显著负相关(P<0.01),与当年5月最低温呈显著正相关(P<0.05);...  相似文献   

17.
Dendroprovenancing studies frequently use site chronologies to identify the origin of archaeological and historical timber. However, radial growth (tree-ring width, TRW) of tree species is influenced by both local and regional climate scales. Here we investigate how the use of annually-resolved Blue Intensity (BI) measurements can enhance dendroprovenancing precision of black pine (Pinus nigra Arn.) and Scots pine (P. sylvestris L.) on the Iberian Peninsula. Principal Component Gradient Analyses (PCGA) was used to assess geographical patterns of annual variation in different TRW and BI proxies of pine trees from two mountain ranges in the Central System and Andalusia in Spain. Local climate-growth relationships were quantified to identify underlying causes of identified groups with diverse growth patterns. Two distinct elevational groups were observed when performing PCGA on latewood BI time series with the response to summer drought as the main factor causing the differences. Both P. nigra and P. sylvestris BI time series were found to be more related to summer drought at low-elevation sites showing an increase in sensitivity at lower latitudes. PCGA of TRW time series allowed to discriminate between trees from Andalusia and Central System within the elevation groups. February and October temperatures were found to be the main climatic factors causing the differences in TRW time series among the high- elevation sites, whereas for low-elevation trees it was the average winter temperature influencing TRW. A subsequent leave-one-out analyses confirmed that including latewood BI time series improves the precision of dendroprovenancing of pine wood in the Iberian Peninsula.  相似文献   

18.
北亚热带马尾松年轮宽度与NDVI的关系   总被引:2,自引:0,他引:2  
北亚热带地处暖温带向亚热带的过渡地区,对环境变化较为敏感。因此,研究北亚热带马尾松年轮宽度与森林NDVI的关系对于揭示陆地生态系统对全球气候变化的响应具有重要意义。以马尾松自然分布北界的南郑县和河南省鸡公山自然保护区为研究地点,利用北亚热带马尾松年轮宽度指数和1982-2006年逐月NOAA/AVHRR的归一化植被指数(NDVI)数据及气候数据,在分析年轮宽度及NDVI与气候因子关系的基础上,重点讨论了北亚热带马尾松径向生长与NDVI之间的关系。结果表明:北亚热带NDVI受水热条件的共同控制,其中与月均温相关性较强,且以正相关为主,与月降水量和干旱度指数多负相关;马尾松的径向生长与上一生长季的温度呈正相关,降水和干旱度指数为负相关,当年生长季内的温度和降水以促进作用为主,而与干旱度指数的关系在两地区内相反;南郑县和鸡公山地区年轮宽度与NDVI年值之间关系均不显著(P>0.05)。单月来讲,南郑县3、4、12月NDVI值与年表显著相关,鸡公山地区9月份的NDVI值与差值年表RES相关性最大;南郑县树木生长受温度影响最大,而鸡公山地区受温度和降水的综合作用。因此,在北亚热带地区,长时间序列的年轮宽度数据并不能很好反应NDVI的长期变化,利用树轮宽度指数来重建北亚热带地区NDVI需要进一步研究。  相似文献   

19.
We investigated whether vessel time series of Holm oak (Quercus ilex L.), a diffuse to semi-ring-porous species, can record a climatic signal which differs from the signal encoded in tree-ring width (TRW). The study was conducted in ten Q. ilex trees from a coppice stand in northeast Spain. Chronologies of TRW, mean vessel area (MVA) and maximum vessel area (MAX) were developed and correlated with climate data, for the period 1985–2004 (20 years). Our results indicate that vessel features contain environmental information that is different from that stored in TRW. MAX chronologies correlate better to early spring precipitation (April–May) than TRW chronologies, and so does MVA of the largest 20–25 vessels from the first third of the ring with late spring precipitation (May–June). Also, the combination of MVA and TRW is a better predictor of summer precipitation. This explorative study clearly shows that vessel features can complement the climatic signal of TRW increasing the resolution of the climate reconstructions for the Mediterranean region.  相似文献   

20.
利用青海不同生境祁连圆柏树木年轮样本,采用3种不同去趋势方法建立树轮年表,结合青海30个气象站的气象资料,分析不同生境和去趋势方法下祁连圆柏径向生长对气候的响应差异。结果表明,祁连山区,生长季前期的平均气温是祁连圆柏树木径向生长的主要限制性因子,NEP树轮标准化宽度年表与生长季前期冬季平均气温相关最好;在柴达木盆地,生长季降水量是该地区树木径向生长的限制性因子,SPL树轮年表对生长季降水量相关较好;在青南高原,祁连圆柏径向生长对春季温度响应最为敏感,而SPL年表与春季温度呈现明显的负相关关系,相关系数达-0.606;而在青海东部地区,祁连圆柏树木径向生长对气候的响应总体不显著。位于青海西部和北部的柴达木盆地和祁连山区祁连圆柏径向生长受西风气候的影响显著,尤其是柴达木盆地,其气候受西风主导;而青南高原受西南季风影响更为显著,该地区祁连圆柏径向生长同时受西南季风气候和海拔高度两方面影响;在青海东部,祁连圆柏径向生长受东亚季风影响更为显著。  相似文献   

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