An important new proxy series, which is one of only 8 in Mann and Jones  and one of only 11 low-frequency proxies in Moberg et al , is the Chinese composite of Yang et al . Unlike the Hockey Team, Prof. Yang promptly provided the underlying data set upon request. Here are some early thoughts.
The Yang article is here. The Yang composite is a weighted average of 9 series, which are all scaled and then plotted below relative to 20th century mean (I’ve done this so that the impact on hockey-stick-ness of each series can be seen more readily.) The 10th cell is the archived version of the series at WDCP. I’ve been able to closely replicate the archived version from the underlying series using weights provided by Yang.
Figure 1. Yang composite, together with underlying series.
The close connection between the Yang Composite and the Dunde series, which is highly weighted (as are the East China documentary and Guliya series), is obvious.
The Great Ghost Lake, Jiaming Lake and Jinchuan sediments all show high MWP values; they are low-weighted and have little impact on the final result. The original articles are in Science in China D and I have been unable to track them down (I’d like pdf’s if anyone can locate them.) The Japanese tree ring series is a dC13 series as I recall [I have this article; I’ll check and update]. One wonders whether this series has been calibrated correctly and whether it should be reversed.
[Note – it does appear to have been used in the reversed orientation.]
The S Tibet tree ring series is obviously discontinuous; I have been unable to track down the original reference. (Wu, X. D., and Z. Y. Lin, Climatic change during the last 2000 years in Tibet, Proceedings of Symposium on Climatic Change, 18–25, Science
Press, Beijing, in Chinese 1981)
The E China documentary series is inaccessible to me. Yang et al say:
The reconstruction of winter temperature from Eastern China are based on 5 proxy observations of changes in distribution of temperature sensitive biota and other climate indices, such as dates of flowering of shrubs, freezing of rivers, or displacements of the boundary of the farming zone [Zhang, 1996]. This record represents a noticeable improvement over the temperature reconstructions of Zhu  and Wang and Wang .
Meritorious as this series may be, it would be nice if the underlying proxy data were made more generally available, as Zhang, P. Y., 1996, Climate change in China during historical times, Scientific and Technological Press, Jinan, 435-436, is in Chinese and, to my knowledge, none of the underlying data is available.
Junipers in the western U.S. are strongly associated with moisture (see Paul Knapp and others) and negligibly associated with temperature. An article on Dulan junipers has been published in the western literature, but I haven’t parsed through the links yet. But it seems plausible to me that these junipers may reflect precipitation rather than temperature. (I once saw a very pretty picture on the Internet about 12 monbths ago of Chinese junipers (I think Dulan) at the edge of a desert, but I haven’t been able to re-locate the picture). Yang et al. say that the junipers are correlated to autumn temperature based on Kang et al  a Chinese-language publication which is inaccessible to me. There is a later western publication, which seems to be by the same group of authors: Zhang et al, 2003.A 2,326-year tree-ring record of climate variability on the northeastern Qinghai-Tibetan Plateau, GRL, 30(14), 1739, doi:10.1029/2003GL017425, which I’ve posted up here.. They state (and this seems consistent with known behavior of similar vegetation in the U.S.:
We find that the annual growth rings mainly reflect variations in regional spring precipitation.
The Dunde version is one of 4 different versions that I’ve seen floating around. In one version, the 13th century was "warm"; in another, it was "cold". Thompson has never alerted anyone to the differences. Perhaps some day, Thompson will deign to archive all the sample information so that these differing versions can be reconciled.
The Dunde and Guliya series are dO18 series, with higher (less negative) dO18 anomalies interpreted as being warmer temperature. The problem is that the relationship between dO18 anomalies and temperature on an annual basis is reversed in monsoon regimes. The most negative dO18 occurs in the summer rather than the winter. Thompson claims that this relationship is reversed on a centennial basis. It seems pretty obvious that more negative dO18 could equally be explained by increased summer precipitation (the "amount effect" in ice core terminology). When you see the Dunde and Guliya dO18 series up against the Dulan juniper series and then recalls that dO18 in the Himalayas immediately reflects the amount of summer precipitation (with any link to temperature being a "tele-connection") , one wonders if the Yang Composite isn’t really a precipitation reconstruction.
Zhang  reported from taxation records that some temperature-sensitive crops in the 13th century had expanded well to the north of present ranges. Obviously this information is at odds with Thompson’s interpretation of Dunde and Guliya ice core dO18. You will understand why I view the Yang Composite as more or less a re-packaging of the Dunde series – which seems to be the active ingredient in it.