摘要
The influence of temperature and precipitation on maximum latewood density （MXD） was mainly discussed in this paper, based on the samples of Picea schrenkiana from the Manas River Basin, Xinjiang, China. The correlation analysis between MXD and instrumental records from the Shihezi Meteorological Station showed that the MXD was positively related to the mean maximum temperature throughout the growing season at high elevations. Comparatively, the ring-width at low altitudes was limited by the precipitation in May-June. The composite chronology by MXD sequences was highly correlated with the mean maximum temperature in July- August （r = 0.54,p 〈 0.001）, which was then reconstructed by the composite chronology. The comparative analysis on the reconstructed temperatures, observed values, and drought indices （Is） revealed that precipitation would affect MXD when the absolute value of Is was greater than 1.5a （i.e., ｜Is｜ 〉 2.5） in the period of 1953-2008 A.D. or close to 1.5σ for 2-3 consecutive years. The response characteristics are linked with the semiarid climate in the study area. In a single year or consecutive years of extreme dryness, the lack of precipitation would limit the thickening oflatewood cell walls and thus impact the MXD. All in all, if a MXD chronology is aimed to reconstruct temperature history, the moisture conditions at the sampling site should be considered prudently.
The influence of temperature and precipitation on maximum latewood density （MXD） was mainly discussed in this paper, based on the samples of Picea schrenkiana from the Manas River Basin, Xinjiang, China. The correlation analysis between MXD and instrumental records from the Shihezi Meteorological Station showed that the MXD was positively related to the mean maximum temperature throughout the growing season at high elevations. Comparatively, the ring-width at low altitudes was limited by the precipitation in May-June. The composite chronology by MXD sequences was highly correlated with the mean maximum temperature in July- August （r = 0.54,p 〈 0.001）, which was then reconstructed by the composite chronology. The comparative analysis on the reconstructed temperatures, observed values, and drought indices （Is） revealed that precipitation would affect MXD when the absolute value of Is was greater than 1.5a （i.e., ｜Is｜ 〉 2.5） in the period of 1953-2008 A.D. or close to 1.5σ for 2-3 consecutive years. The response characteristics are linked with the semiarid climate in the study area. In a single year or consecutive years of extreme dryness, the lack of precipitation would limit the thickening oflatewood cell walls and thus impact the MXD. All in all, if a MXD chronology is aimed to reconstruct temperature history, the moisture conditions at the sampling site should be considered prudently.
基金
This research was supported by the National Natural Science Foundation of China （Grant Nos. 41275120, 41271120, and 41301041） and ＂135＂ Strategic Research Project of IGSNRR, CAS （No. 2012ZD001）. Ring-density experiment supports from the Laboratory for Climate Studies, China Meteorological Administration are also appreciated.
