Table 4. Pearson correlation coefficients (1956–2011) between STD chronologies and optimal seasonal precipitaiton and temperature and the same correlations using first-order differential series.

	Precipitation(P7-C6)		Temperature (P12-C2)
	R	Rac1	R	Rac1
H	0.6	0.62	0.24	0.04
MH	0.74	0.69	0.46	0.02
ML	0.68	0.62	0.41	−0.03
L	0.61	0.66	0.25	−0.06
All	0.68	0.66	0.34	−0.01

R: correlation coefficient; R_ac1: correlation coefficient of the first-order differential series. H, MH, ML, L, All are site codes for different elevations (see Table 1). Precipitation (P7-C6) is the accumulated precipitation from previous July to current June. Temperature (P12-C2) is the mean temperature from previous December to current February.