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To extend the historical temperature record in the permafrost region of Northeast China, we reconstruct the regional ground surface temperature (GST) for the past four centuries based on a network of Dahurian larch (Larix gmelinii Rupr.) tree-ring width chronologies. Seven standard tree-ring chronologies, which correlate well with each other, are averaged to create a regional mean chronology. GST is the major limiting factor for tree growth in this region. The optimum range of GSTs is from 30 May to 26 August (summer GST), identified by combining the days on which tree growth was strongly influenced by the daily GST data. The summer GST was significantly correlated with the regional mean chronology (r = 0.704, p < 0.001) over the common period 1971-2008 and was reconstructed for the period 1587-2008. The reconstructed GST accounts for 49.4% of the actual variance in the GST over the period 1971-2008 and captures four warm periods (1597-1603, 1716-1723, 1781-1788, and 1925-1929) and three cold periods (1639-1647, 1686-1711, and 1799-1805). The reconstructed GST is consistent with the northern hemisphere temperature in the Little Ice Age, and the warming rate from 1857 to 2008 is similar to a previously reported temperature reconstruction in the Xiao Xing’an Mountains. The low frequency of the reconstructed GST is well matched with that of the permafrost thawing depth. The reconstructed GST represents the longest temperature record in this study region and may be used as a reference for the permafrost thawing depth. [ABSTRACT FROM AUTHOR]

We present a well-verified precipitation reconstruction ( r = 0.612, p < 0.01), spanning 1741 to 1998, for a relatively humid monsoon region from southern Northeast China and the northern Korean peninsula, based on tree rings from Chinese pine and Korean pine. We then investigate the variability of the reconstruction, and identify the leading rainfall patterns and regional dryness and wetness modes during the latest 2.5 centuries. This reconstruction shows that three persistent dry decades occurred during the 1840s, 1910s and 1850s and the three wettest decades occurred during the 1770s, 1820s and 1930s. The five years with lowest rainfall were 1759, 1917, 1841, 1747 and 1839, and 1770, 1938, 1819, 1941 and 1822 were the five years with highest rainfall, respectively. As indicated by the spatial correlation patterns, the reconstruction also exhibits regional characteristics. The variation of reconstructed rainfall significantly corresponds to East Asian monsoon. [ABSTRACT FROM AUTHOR]

The southern part of northeast China has experienced a marked warming and drying climate. We provide dendrochronological evidence for atmospheric CO fertilization and the impacts of warming on Chinese pine ( Pinus tabulaeformis) growth. The results of this study show that increased temperature has a negative effect on pine growth during a major part of the growing season and a weakly positive effects on growth during the remaining portion of the year. The monthly temperatures explain ca. 20 % of the total variance in the annual radial growth of Chinese pine from 1901 to 2009. An increase of approximately 3-5 °C is the maximum that Chinese pine can tolerate in this region with an annual rainfall of 500-700 mm. Our results suggest a that there is a proportional response to warming only up to a maximum of 1 °C warming, and indicate the complexitiesof succession in forest ecosystems in terms of adaptation and evolution in local pine populations under a rapid warming condition. In addition, increasing atmospheric CO concentrations have a positive effect on tree growth. This effect can be detected with conventional dendrochronological methods. [ABSTRACT FROM AUTHOR]