Intensified variability of the El Niño–Southern Oscillation enhances its modulations on tree growths in southeastern China over the past 218 years

Abstract

Lack of long‐term tree‐ring records in the core regions of the Asian summer monsoon in southeastern China limits our ability of evaluating the current climate change in a historical context. In this study, we developed the first 218‐year tree‐ring chronology (1798–2015) of Pinus massoniana in Zhangping area, Fujian Province, humid subtropical China. This chronology is positively correlated with winter–spring (January–March) temperature (r = 0.359, p < .01) and summer (July–September) precipitation (r = 0.351, p < .01). Although the correlations between our tree rings with sea surface temperatures (SSTs) are not very high, the correlation pattern is very close to the correlation pattern with the El Niño–Southern Oscillation variability (ENSO). These suggest that the ENSO could be the major large‐scale regulator on the growth of our tree rings. The strength of the correlations between our tree rings and the ENSO (r = 0.30, N = 66) matches closely with the ENSO variability during 1950–2015. The modulations of the ENSO on regional tree growth have been the most conspicuous since the 1950s, which corresponds to its enhanced inter‐annual variability. The extreme growth anomalies match quite well with the extreme years of the moisture‐sensitive chronologies. The dry epoch from 1935 to 1958 is the most severe long‐lasting drought in our tree rings, which is a widely distributed pattern in southeastern China and is likely modulated by the La Niña‐like modes in that period.

A 241-Year Cryptomeria fortune Tree-Ring Chronology in Humid Subtropical China and Its Linkages with the Pacific Decadal Oscillation

“…During the 1920s-1930s and 1945-1995, the radial growth of trees was negatively correlated with observations of the PDO (p < 0.05). Linkages between climate sensitive tree rings and the PDO are also seen in other regions of Southeast China [18][19][20]. The correlation between the observation PDO and the reconstruction PDO Figure 6.…”

“…The radial growth of coniferous tree rings in southeastern China, such as the lower reaches of the Yangtze River basin and the Fujian Province, is widely seen to be limited by summer drought and winter coldness [12][13][14][15][16]20]. Tree growth is subjected not only to the influence of current year's climate, but also the previous year's [35].…”

Early summer hydroclimatic signals are captured well by tree-ring earlywood width in the eastern Qinling Mountains, central China

“…The self-calibrated PDSI (scPDSI) and SPEI were also chosen as hydroclimatic factors. Here we used the scPDSI instead of PDSI because it has solved the PDSI problems in spatial comparisons by calculating the duration factors (weighting coefficients for the current moisture anomaly and the previous drought severity) based on the characteristics of the climate at a given location (Wells et al, 2004). The regional scPDSI was calculated by averaging the CRU (Climate Research Unit) scPDSI grids (van der Schrier et al, 2013) over the area between 32 to 34.5 • N and 111 to 112 • E (Fig.…”

“…Some TRW chronologies within the monsoon region showed weak or unstable hydroclimatic signals (e.g., Li et al, 2016;Shi et al, 2012;Wang et al, 2018), making them unsuitable to derive reliable reconstructions. By contrast, intra-annually resolved tree-ring width (i.e., earlywood width, EWW, and latewood width, LWW) provided stronger hydroclimatic signals than TRW in some cases Zhao et al, 2017a).…”

“…Meanwhile, tree growth at an adjacent site was found to be more restricted by the drought index, represented by the wellknown PDSI (Palmer Drought Severity Index), rather than by precipitation or temperature (Peng et al, 2014). Briefly, the PDSI monitors the cumulative departure of surface water balance in terms of the difference between the amount of precipitation required to retain a normal water-balance level and the amount of actual precipitation (Palmer, 1965;Wells et al, 2004). In addition, the SPEI, a drought index representing water balance in the form of difference between precipitation and potential evapotranspiration (Vicente-Serrano et al, 2010), was reported to constrain latewood growth at a well-drained site in the core region of EASM (Zhao et al, 2017a, b).…”