The Radial Growth of Schrenk Spruce (Picea schrenkiana Fisch. et Mey.) Records the Hydroclimatic Changes in the Chu River Basin over the Past 175 Years

Abstract

The Chu River is one of the most important rivers in arid Central Asia. Its discharge is affected by climate change. Here, we establish a tree-ring chronology for the upper Chu River Basin and analyze the relationships between radial growth, climate, and discharge. The results show that the radial growth of Schrenk spruce (Picea schrenkiana Fisch. et Mey.) is controlled by moisture. We also reconstruct a 175-year standardized precipitation-evapotranspiration index (SPEI) for the Chu River Basin. A comparison of the reconstructed and observed indices reveal that 39.5% of the variance occurred during the calibration period of 1952–2014. The SPEI reconstruction and discharge variability of the Chu River show consistent long-term change. They also show that the Chu River Basin became increasingly dry between the 1840s and the 1960s, with a significant drought during the 1970s. A long and rapid wetting period occurred between the 1970s and the 2000s, and was followed by increasing drought since 2004. The change in the SPEI in the Chu River Basin is consistent with records of long-term precipitation, SPEI and Palmer Drought Severity Indices (PDSI) in other proximate regions of the western Tianshan Mountains. The hydroclimatic change of the Chu River Basin may be associated with westerly wind. This study is helpful for disaster prevention and water resource management in arid central Asia.

Impacts of Global Warming on the Radial Growth and Long-Term Intrinsic Water-Use Efficiency (iWUE) of Schrenk Spruce (Picea schrenkiana Fisch. et Mey) in the Sayram Lake Basin, Northwest China

“…Whether radial growth is negatively related to temperature and VPD or positively related to relative humidity and precipitation, these results indicate that the main environmental factor affecting the radial growth of trees is water stress, especially during the growing season. Many other studies have confirmed that the radial growth of Schrenk spruce is limited by water stress during the main growing season [26][27][28][29][30][31][32][33][34][35]. Yuan et al [26] found that tree-ring width chronologies are most closely correlated with the number of precipitation days between 20 May and 8 June in the Urumqi River Basin.…”

“…All pooled samples were grounded into powder in a ball mill (MM 400, Retsch GmbH, Germany), and the α cellulose was extracted using the method of Brendel et al [45]. This method has been widely used in dendroclimatology studies [34,35,46].…”

“…There are a large number of Schrenk spruce (Picea schrenkiana Fisch. et Mey) virgin forests in this region and this species has been shown to be suitable for dendrochronological study [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. However, few studies have discussed the relationship between C a , climate, radial growth, and iWUE in the Tianshan Mountains [39,40].…”

Differences in the Responses of Tree-Ring Stable Carbon Isotopes of L. sibirica and P. schrenkiana to Climate in the Eastern Tianshan Mountains

“…L. sibirica and P. schrenkiana, which are both endemic to the mountains and capable of withstanding cold and drought, are well-suited to dendroclimatological studies. In arid inland Asia, most dendroclimatological studies are based on tree-ring width parameter reconstruction, and tree-ring stable isotope studies are scarce [21][22][23][24]. Zhang et al [25,26] reconstructed temperature changes in southeast Kazakhstan based on tree-ring stable carbon isotopes and combined the tree-ring width and stable carbon isotopes to reconstruct glacier mass balance changes.…”

Tree-Ring Width and Carbon Isotope Chronologies Track Temperature, Humidity, and Baseflow in the Tianshan Mountains, Central Asia

“…Long-scale hydrological and climate change chronologies obtained from tree-ring data have unparalleled advantages and great potential in this respect. Since the 1970s, tree-ring climatologists have carried out plenty of tree-ring research work in the Tianshan Mountains area and numerous reconstructions of streamflow, precipitation, and drought have been developed based on tree-ring data [19][20][21][22][23][24][25][26][27][28]. Such achievements include research on the reconstruction and analysis of the precipitation in the Ili River Basin in the west of the Tianshan Mountains over 314 years [29], the relationship between the climate growth volume and the climate of the spruce rings in the west of the Tianshan Mountains [30], and changes in the cold and warm characteristics in the Ili River Basin in Xinjiang over the past 250 years [31].…”