Abstract. Trees record climatic conditions during their growth, and
tree rings serve as proxy to reveal the features of the historical climate
of a region. In this study, we collected tree-ring cores of hemlock forest
(Tsuga forrestii) from the northwestern Yunnan area of the southeastern Tibetan Plateau
(SETP) and created a residual tree-ring width (TRW) chronology. An analysis
of the relationship between tree growth and climate revealed that
precipitation during the non-growing season (NGS) (from November of the
previous year to February of the current year) was the most important
constraining factor on the radial tree growth of hemlock forests in this
region. In addition, the influence of NGS precipitation on radial tree
growth was relatively uniform over time (1956–2005). Accordingly, we
reconstructed the NGS precipitation over the period spanning from 1600–2005.
The reconstruction accounted for 28.5 % of the actual variance
during the common period of 1956–2005. Based on the reconstruction, NGS was
extremely dry during the years 1656, 1694, 1703, 1736, 1897, 1907,
1943, 1982 and 1999. In contrast, the NGS was extremely wet during the
years 1627, 1638, 1654, 1832, 1834–1835 and 1992. Similar variations
of the NGS precipitation reconstruction series and Palmer Drought Severity
Index (PDSI) reconstructions of early growing season from surrounding
regions indicated the reliability of the present reconstruction. A
comparison of the reconstruction with Climate Research Unit (CRU) gridded
data revealed that our reconstruction was representative of the NGS
precipitation variability of a large region in the SETP. Our study provides
the first historical NGS precipitation reconstruction in the SETP which
enriches the understanding of the long-term climate variability of this
region. The NGS precipitation showed slightly increasing trend during the
last decade which might accelerate regional hemlock forest growth.
Reconstruction of southeast Tibetan Plateau summer climate using tree ring δ<sup>18</sup>O: moisture variability over the past two centuries