LAUSR

Abstract A greater amplitude and higher mean intensity of the El Nino phenomenon have both been observed in the last few decades. In order to determine how tree growth and recent El Nino variabilities are associated within the East Asia subtropical forest (EASF), we conducted a dendroecological study using a network of 25 zonal tree-ring width chronologies from Pinus massoniana Lamb. trees distributed across extensive latitudinal (23 to 33°N) and elevational (77 to 1285 m) gradients in EASF. Using principal component analysis (PCA), bootstrapped correlations, spatial correlations, and mediation analysis, the associations among interannual tree radial growth (over the period of 1987 to 2015), El Nino variability, and the climate variables were tested. Our study indicates that the radial growth of P. massoniana is generally stimulated by climate anomalies (warmer/sunnier spring and fall and lower water deficit from winter to summer) positively associated with NINO3.4 index. Moreover, the results also demonstrate that the positive radial growth response to El Nino is significantly strengthened from south to north in the EASF, which could be attributed to tree growth benefiting more from the El Nino-related water deficit release and October sunshine increase in northern habitats, which are traditionally colder and drier than the south.