DENDROCLIMATOLOGICAL STUDIES OF PICEA LIKIANGENSIS AND TSUGA DUMOSA IN LIJIANG, CHINA

IAWA Journal ◽  
2009 ◽  
Vol 30 (4) ◽  
pp. 435-441 ◽  
Author(s):  
Gaiai Guo ◽  
Zong-Shan Li ◽  
Qi-Bin Zhang ◽  
Ke-Ping Ma ◽  
Conglong Mu

Expansion of climate proxy records over space is needed for improving our knowledge of past climate variability. Here we report on a 112-year tree-ring chronology of Picea likiangensis (Franch.) E.Pritz. and a 165- year tree-ring chronology of Tsuga dumosa (D.Don) Eichler for the Lijiang area, northwestern Yunnan, China. Mean correlation coefficients of tree-ring width series among individual trees are 0.48 for P. likiangensis and 0.45 for T. dumosa, indicating a growth response to common environmental variability. Analysis of climate-growth relationships shows that the radial growth of P. likiangensis is mainly negatively correlated with temperature from December of the prior growth year to May of the growth year, and that of T. dumosa is mainly positively correlated with precipitation of January and May in the growth year. We further found that the chronology of T. dumosa can be used to reconstruct the May-June Palmer Drought Severity Index. The reconstruction shows that major wet periods occurred in the 1860s, 1910s and 1940s, and drought periods in 1892–1905, 1914–1924 and 1928–1938. The moisture condition of the late 20th century is characterized by a near-normal state from the 1950s to the 1970s and an increasing trend from 1982 to 2003.

1993 ◽  
Vol 23 (5) ◽  
pp. 846-853 ◽  
Author(s):  
D.C. West ◽  
T.W. Doyle ◽  
M.L. Tharp ◽  
J.J. Beauchamp ◽  
W.J. Platt ◽  
...  

Longleaf pine (Pinuspalustris Mill.) tree-ring data were obtained from an old-growth stand located in Thomas County, Georgia. The tree-ring chronology from the pine stand is composed of a collection of cores extracted from 26 trees ranging in age from approximately 100 to 400 years. These cores were prepared, dated, and measured, and the resulting data were examined with dendrochronological and statistical techniques. Beginning in approximately 1950 and continuing to the present, annual increments of all age classes examined in this study have increased, resulting in an average annual ring increment approximately 40% greater in 1987 than in 1950. When compared with expected annual increment, the increase for 100- to 150-year-old trees is approximately 45%, while the increase for 200- to 400-year-old trees is approximately 35%. In terms of stand-level aboveground biomass accumulation, the increased growth has resulted in approximately 5% more biomass than expected. The increased growth cannot be explained by disturbance; stand history; or trends in precipitation, temperature, or Palmer drought severity index over the last 57 years. Increased atmospheric CO2 is a possible explanation for initiation of the observed trend, while SOx and NOx may be augmenting continuation of this phenomenon.


2020 ◽  
Vol 16 (2) ◽  
pp. 783-798
Author(s):  
Sarir Ahmad ◽  
Liangjun Zhu ◽  
Sumaira Yasmeen ◽  
Yuandong Zhang ◽  
Zongshan Li ◽  
...  

Abstract. The rate of global warming has led to persistent drought. It is considered to be the preliminary factor affecting socioeconomic development under the background of the dynamic forecasting of the water supply and forest ecosystems in West Asia. However, long-term climate records in the semiarid Hindu Kush range are seriously lacking. Therefore, we developed a new tree-ring width chronology of Cedrus deodara spanning the period of 1537–2017. We reconstructed the March–August Palmer Drought Severity Index (PDSI) for the past 424 years, going back to 1593 CE. Our reconstruction featured nine dry periods (1593–1598, 1602–1608, 1631–1645, 1647–1660, 1756–1765, 1785–1800, 1870–1878, 1917–1923, and 1981–1995) and eight wet periods (1663–1675, 1687–1708, 1771–1773, 1806–1814, 1844–1852, 1932–1935, 1965–1969, and 1990–1999). This reconstruction is consistent with other dendroclimatic reconstructions in West Asia, thereby confirming its reliability. The multi-taper method and wavelet analysis revealed drought variability at periodicities of 2.1–2.4, 3.3, 6.0, 16.8, and 34.0–38.0 years. The drought patterns could be linked to the large-scale atmospheric–oceanic variability, such as the El Niño–Southern Oscillation, Atlantic Multidecadal Oscillation, and solar activity. In terms of current climate conditions, our findings have important implications for developing drought-resistant policies in communities on the fringes of the Hindu Kush mountain range in northern Pakistan.


Forests ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 505 ◽  
Author(s):  
Feng Chen ◽  
Tongwen Zhang ◽  
Andrea Seim ◽  
Shulong Yu ◽  
Ruibo Zhang ◽  
...  

Coniferous forests cover the mountains in many parts of Central Asia and provide large potentials for dendroclimatic studies of past climate variability. However, to date, only a few tree-ring based climate reconstructions exist from this region. Here, we present a regional tree-ring chronology from the moisture-sensitive Zeravshan juniper (Juniperus seravschanica Kom.) from the Kuramin Range (Tajikistan) in western Central Asia, which is used to reveal past summer drought variability from 1650 to 2015 Common Era (CE). The chronology accounts for 40.5% of the variance of the June–July self-calibrating Palmer Drought Severity Index (scPDSI) during the instrumental period (1901 to 2012). Seven dry periods, including 1659–1696, 1705–1722, 1731–1741, 1758–1790, 1800–1842, 1860–1875, and 1931–1987, and five wet periods, including 1742–1752, 1843–1859, 1876–1913, 1921–1930, and 1988–2015, were identified. Good agreements between drought records from western and eastern Central Asia suggest that the PDSI records retain common drought signals and capture the regional dry/wet periods of Central Asia. Moreover, the spectral analysis indicates the existence of centennial (128 years), decadal (24.3 and 11.4 years), and interannual (8.0, 3.6, 2.9, and 2.0 years) cycles, which may be linked with climate forces, such as solar activity and El Niño-Southern Oscillation (ENSO). The analysis between the scPDSI reconstruction and large-scale atmospheric circulations during the reconstructed extreme dry and wet years can provide information about the linkages of extremes in our scPDSI record with the large-scale ocean–atmosphere–land circulation systems.


2019 ◽  
Vol 15 (4) ◽  
pp. 1251-1273 ◽  
Author(s):  
Robert Tardif ◽  
Gregory J. Hakim ◽  
Walter A. Perkins ◽  
Kaleb A. Horlick ◽  
Michael P. Erb ◽  
...  

Abstract. The Last Millennium Reanalysis (LMR) utilizes an ensemble methodology to assimilate paleoclimate data for the production of annually resolved climate field reconstructions of the Common Era. Two key elements are the focus of this work: the set of assimilated proxy records and the forward models that map climate variables to proxy measurements. Results based on an updated proxy database and seasonal regression-based forward models are compared to the LMR prototype, which was based on a smaller set of proxy records and simpler proxy models formulated as univariate linear regressions against annual temperature. Validation against various instrumental-era gridded analyses shows that the new reconstructions of surface air temperature and 500 hPa geopotential height are significantly improved (from 10 % to more than 100 %), while improvements in reconstruction of the Palmer Drought Severity Index are more modest. Additional experiments designed to isolate the sources of improvement reveal the importance of the updated proxy records, including coral records for improving tropical reconstructions, and tree-ring density records for temperature reconstructions, particularly in high northern latitudes. Proxy forward models that account for seasonal responses, and dependence on both temperature and moisture for tree-ring width, also contribute to improvements in reconstructed thermodynamic and hydroclimate variables in midlatitudes. The variability of temperature at multidecadal to centennial scales is also shown to be sensitive to the set of assimilated proxies, especially to the inclusion of primarily moisture-sensitive tree-ring-width records.


2018 ◽  
Vol 91 (1) ◽  
pp. 81-95 ◽  
Author(s):  
Magdalena Opała-Owczarek ◽  
Tadeusz Niedźwiedź

AbstractWe developed a 1108 yr chronology of tree-ring widths, based on 64 Himalayan pencil juniper (Juniperus semiglobosa Regel) trees, for the Pamir-Alay Mountains, central Asia. Dendroclimatological analysis demonstrates that precipitation has significant effects on tree growth in the semiarid mountainous area of northwestern Tajikistan located on the edge of the great midlatitude Karakum and Kyzylkum deserts. The highest level of linear correlation (r=0.67) is observed between tree growth and seasonalised winter (previous December–February) precipitation. Our studies also show that moisture (precipitation/Palmer Drought Severity Index) from the previous June to the current September was the dominant climatic factor accounting for interannual variations in tree-ring width, suggesting that this should be considered in climate reconstruction. Using the transfer function method, we reconstructed the region’s drought history over the period AD 908–2015. The results of this moisture reconstruction showed that the most recent millennium was characterised by series of dry and wet stages. The driest periods occurred before 1000, 1200–1250, and at the end of the eighteenth century and beginning of the nineteenth century. The wettest conditions existed in 1650–1700 and after 1990.


2019 ◽  
Vol 31 (6) ◽  
pp. 2245-2254 ◽  
Author(s):  
Samresh Rai ◽  
Binod Dawadi ◽  
Yafeng Wang ◽  
Xiaoming Lu ◽  
Huang Ru ◽  
...  

Abstract The Himalayas are characterized by a broad gradient of bioclimatic zones along their elevation. However, less is known how forest growth responds to climatic change along elevation. In this study, four standard tree-ring width chronologies of Himalayan fir (Abiesspectabilis) were developed, spanning 142–649 years along an elevation gradient of 3076–3900 m a.s.l. Principal component analysis classified the four chronologies into two groups; the ones at lower elevations (M1 and M2) and higher elevations (M3 and M4) show two distinct growth trends. Radial growth is limited by summer (June–August) precipitation at M3, and by precipitation during spring (March–May) and summer at M4. It is limited by spring temperatures and winter precipitation (December–February) at M1. Tree-ring width chronologies also significantly correlate with winter and spring Palmer Drought Severity Index (PDSI) at M1, and with summer PDSI at M3 and M4. Thus, Himalayan fir growth at high elevations is mainly limited by moisture stress rather than by low temperatures. Furthermore, the occurrence of missing rings coincides with dry periods, providing additional evidence for moisture limitation of Himalayan fir growth.


2018 ◽  
Vol 45 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Tongwen Zhang ◽  
Shulong Yu ◽  
Yujiang Yuan ◽  
Liping Huang ◽  
Shengxia Jiang

Abstract Forty-one living larch (Larix principis-rupprechtii) trees collected from two sampling sites in 1310–1530 m a.s.l. in the southern Greater Higgnan Mountains in the northeastern China are used to develop a regional tree-ring width chronology. The credible chronology spans 185 years from 1830 to 2014. The results of correlation analyses indicate that moisture is the main climatic factor controlling radial growth of larch trees in this mountainous area. Spatial correlation proves that the regional tree-ring width chronology contains climatic signals representative for a large area including the eastern Mongolian Plateau and Nuluerhu Mountains. A comparison between the newly developed chronology and a May–July Palmer Drought Severity Index (PDSI) reconstruction for the Ortindag Sand Land reveals similar variations, particularly in the low-frequency domain. The tree-ring records also capture a severe and sustained drying trend recorded in the 1920s across a wide area of northern China.


2018 ◽  
Vol 6 (2) ◽  
pp. 359-368 ◽  
Author(s):  
Yu Liu ◽  
Huiming Song ◽  
Changfeng Sun ◽  
Yi Song ◽  
Qiufang Cai ◽  
...  

AbstractThe numerous temperature and precipitation reconstructions in China based on tree-ring-width data have played significant roles in furthering the understanding of past climate changes. However, the geographical variability in the responses of trees to climate variations in China remains largely undetermined. Here, we describe an important spatial boundary in the response of trees to climate variations, namely the 600-mm annual precipitation isoline. We found that, to the north of this line, tree-ring widths are usually positively correlated with precipitation and negatively correlated with growing-season temperature. To the south of this line, the tree-ring widths respond positively to temperature, and winter half-year temperatures are the main reconstructed parameters, especially on the third topographical step of China. We also found that precipitation reconstructions based on tree-ring data and the Palmer Drought Severity Index almost exclusively fall in the region of the 200- to 600-mm annual precipitation isolines, not other regions. Our findings indicate that, when using multiple tree-ring-width chronologies for large-scale past climate reconstructions, the climatic signal of each tree-ring-width series should be carefully considered.


2021 ◽  
Author(s):  
Maierdang Keyimu ◽  
Zongshan Li ◽  
Bojie Fu ◽  
Guohua Liu ◽  
Weiliang Chen ◽  
...  

Abstract. Trees record climatic conditions during their growth, and tree-rings serve as a proxy to reveal the features of the historical climate of a region. In this study, we collected tree-ring cores of forest hemlock (Tsuga forrestii) from the northwestern Yunnan area of the southeastern Tibetan Plateau (SETP), and created a residual tree-ring width (TRW) chronology. An analysis of the relationship between tree growth and climate revealed that precipitation during the non-growth season (NGS) (from November of the previous year to February of the current year) was the most important constraining factor on the radial tree growth of forest hemlock in this region. In addition, the influence of NGS precipitation on radial tree growth was relatively uniform over time (1956–2005). Accordingly, we reconstructed the NGS precipitation over the period spanning from A.D. 1475–2005. The reconstruction accounted for 28.5 % of the actual variance during the common period 1956–2005, and the leave-one-out verification parameters indicated the reliability of the reconstruction. Based on the reconstruction, NGS was extremely dry during the years A.D. 1475, 1656, 1670, 1694, 1703, 1736, 1897, 1907, 1943, 1969, 1982, and 1999. In contrast, the NGS was extremely wet during the years A.D. 1491, 1536, 1558, 1627, 1638, 1654, 1832, 1834–1835, and 1992. Similar variations of the NGS precipitation reconstruction series and Palmer Drought Severity Index (PDSI) reconstructions from surrounding regions indicated the reliability of the reconstruction. A comparison of the reconstruction with Climate Research Unit (CRU) gridded data revealed that our reconstruction was representative of the NGS precipitation variability of a large region in the SETP.


Forests ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 674 ◽  
Author(s):  
Jian Yu ◽  
Sher Shah ◽  
Guang Zhou ◽  
Zhenzhao Xu ◽  
Qijing Liu

We developed two tree-ring width chronologies of Mongolian Scots pine (Pinus sylvestris var. mongolica) from the low elevation forest of the northern Daxing’anling Mountains of Inner Mongolia. Although the two chronologies come from different sampling sites, significant correlations existed among the chronologies (r = 0.318), and the first principal component (PC1) accounted for 65.9% of total variance over their common period 1792–2016. Climate-growth correlation analysis revealed that the previous June and July Palmer drought severity index (PDSIp6-7) was the main climatic factor controlling tree-ring growth. Using a linear regression model, we reconstructed the PDSIp6-7 for the past 225 years (1792–2016). The reconstruction satisfied required statistical calibration and validation tests, and represented 38.6% of the PDSI variance recorded by instruments over the period 1955–2016. Six wet and five dry periods were revealed during these 225 years. The drought of 1903–1927 was the most severe drought in the study area in the last 225 years. Comparison with other tree-ring-based moisture-sensitive sequences from nearby regions confirmed a high degree of confidence in our reconstruction. The results of a spatial climate correlation analysis with a gridded PDSI dataset revealed that our reconstructions contained strong regional drought signals for the southern Stanovoy Range and the northern Daxing’anling Mountains. The power spectrum revealed the existence of significant frequency cycles, which may be linked to large-scale atmospheric-oceanic variability, such as the El Niño-Southern Oscillation, solar activity, and the North Atlantic Oscillation.


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