Dendroclimatologists have told us that they want to root out misinformation like anyone thinking that white spruce chronologies from northern Alberta archived at the ITRDB are temperature proxies. I’ve conveyed that message to CA readers and I’m happy to report that, as far as I know, CA readers agree that northern Alberta white spruce chronologies archived at the ITRDB are not temperature proxies.
Following that successful mission, I’ve got a project for the Dendro Truth Squad. Shao et al report that Qilianshan junipers are (unsurprisingly) said to be limited by precipitation. The picture below shows Qilianshan junipers and does not contradict the report of Shao et al that they are precipitation limited. (The closing picture in the presentation by Shao et al, see below, evidences precipitation limitation even more dramatically, but, upon checking, it turns out that Dr Shao does not know where this picture comes from and it appears that the picture was inserted in her presentation for dramatic effect only.)
Although Qilianshan junipers are said to be precipitaiton limited, Qilianshan juniper chronologies are directly used as temperature proxies in Crowley and Lowery 2000 and Yang et al 2002, with the Yang composite being used as a proxy in many Hockey Team studies: Mann and Jones 2003, Moberg et al 2005, Osborn and Briffa 2006, Hegerl et al 2006. Obviously this looks like a good mission for the Dendro Truth Squad.
Shao et al, the authors of the presentation cited above, have an article online at PAGES about the development of an 11-site chronology in the Dulan-Delingha area, with the following location map. The sites are all between 3700 and 3910 m. Thus there are at virtually the same latitude and altitude as the bristlecones in White Mountains CA.
The authors state (and this finding is echoed in all other articles about the area):
Precipitation and mean maximum temperature in May and June are highly limiting to growth of Qilian Juniper in study area;
Other articles about Qilianshan junipers in the past few years are listed in the references below; long chronologies located approx. 65-150 km south of these sites are discussed in Zhang, et al., 2003. Zhang et al 2007 and Sheppard et al 2005 also discuss this area. In every study, spring precipitation is said to be the limited factor – unsurprisingly when one looks at the sites. Liu et al 2006 say that precipitation is limiting for both upper and lower treelines.
Crowley and Lowery 2000
On slide 3, the authors cite Wang et al (Kexue Tongbao 1983) as being a prior reports on Qilianshan junipers. Crowley and Lowery 2000, one of the most cited multiproxy studies and a study that is often used to make the case that warmth in the MWP was regional, includes as one of their small collection of proxies was:
” a tree ring record from the Qilian Shan Mountains of western China (25)”
Reference (25) is:
25. Wang, Y., Guangyuan, L., Zhang, X., and Li, C. 1983. The relationships between the tree rings of Qilianshan juniper and climatic change and glacial activity during the past 1000 years in China. Kexue Tongbao, 28, 1647—1652.
So Crowley and Lowery 2000 used Qilianshan junipers, known to be a precipitation proxy. Over to you, Dendro Truth Squad.
Yang et al 2002
The story of the Qilianshan (Dulan) junipers doesn’t end with Crowley and Lowery 2000. Yang et al 2002, widely used in Hockey Team studies (Mann and Jones 2003; Moberg et al 2005; Osborn and Briffa 2006; Hegerl et al 2006) also included a “Dulan tree-ring record” , reported as follows:
Four of the series are related to the Tibetan Plateau (TP) (Guliya ice core, Dunde ice core, Dulan tree-ring record in the northeastern TP and a composite tree-ring record from the southern TP) and 5 series were obtained from Eastern China and Japan.
As a source for their Dulan tree ring record, Yang et al 2002 cite Yang , B., X. C. Kang, and Y. F. Shi, 2000. Decadal climatic variations indicated by Dulan tree ring and comparison with other proxy data in China of the last 2000 years, Chinese Geographical Science, 4, 193—201. I haven’t been able to locate Yang et al 2000, but coauthor Kang is also coauthor of Zhang et al 2003 Zhang, Q.-B., Cheng, G., Yao, T., Kang, X. and Huang, J., 2003: A 2,326-year tree-ring record of climate variability on the northeastern Qinghai-Tibetan Plateau. Geophysical Research Letters, Vol. 30(14), 1739, doi: 10.1029/2003GL017425) which appears to describe the same sites (or very similar sites) as Yang et al 2000. Zhang et al:
Our study area is located in Dulan (35 50 – 36 30N, 97 40 – 98 20E) of northeastern Qinghai-Tibetan Plateau (Figure 1)… Sabina przewalskii Kom. is the most important single tree species on south-facing mountain slopes, and usually grows scatterly in open stands at an elevation between 3100 m and 3800 m. … Here we present a 2326-year tree-ring chronology of Sabina przewalskii Kom. for Dulan area of northeastern Qinghai-Tibetan Plateau. We find that the annual growth rings mainly reflect variations in regional spring precipitation…. Twenty samples from the ancient tombs and 68 samples from Dulan living trees, among which 55 samples were collected and examined previously in a separate study [Kang et al., 1997], were successfully crossdated. …The growth of sabina trees is under stress as indicated by the stripbark morphology and partial dieback of some upper limbs.
The most recent article on the area Zhang et al (Dendrochronologia 2007) also stated that spring precipitation was the limiting factor in Qilianshan juniper (Sabina).
Climate—growth response function and correlation analyses show that radial growth of Sabina [juniper] trees is positively associated with total precipitation in May and June of the growth year. Multidecadal variation in Delingha tree-ring chronology exhibits similar pattern with those of Dulan and Wulan chronologies of the nearby areas, suggesting that spring precipitation is a major factor limiting the growth of Sabina trees over a large spatial scale.
So I think that we can conclude that these Qilianshan junipers do not qualify as temperature proxies within any criteria of the Dendro Truth Squad. OK, angry dendroclimatologists, take up your keyboards and demand that the offending authors correct their misinformation.
Update, Apr 15, 2007: This post originally included a picture from the final slide of a presentation by Shao et al here entitled “A Dendroclimatic Study of Qilian Juniper in the northeast Qinghai-Xizang (Tibet) Plateau”, which shows a photograph of a tree in a desert. A reader wrote in that, despite its position in the Shao et al presentation, the tree was not a Dulan juniper. I corresponded with Dr Shao and she said that she was unable to recall where the photograph was taken, but said that it was not a Dulan juniper. The photograph has been transferred to this thread, where other “tree in desert” pictures from western China are shown. Please note the excellent satellite photo submitted by Willis Eschenbach below here which shows the sampling areas – brownish looking south-facing mountains to the west of Qinghai Lake.
Kang, X., Graumlich, L.J., Sheppard, P.R. 1997. A 1,835 year tree-ring chronology and its preliminary analyses in Dulan region, Qinghai. Chinese Science Bulletin 42(13):1122-1124. (also cited as Quatertnary Sciences)
LIU Yu , AN Zhisheng , MA Haizhou , CAI Qiufang , LIU Zhengyu , John K. Kutzbach , SHI Jiangfeng , SONG Huiming , SUN Junyan , YI Liang , LI Qiang , YANG Yinke , WANG Lei , 2006. Precipitation variation in the northeastern Tibetan Plateau recorded by the tree rings since 850 AD and its relevance to the Northern Hemisphere temperature Science in China Series D: Earth Sciences (Chinese. I’ve only looked at the English abstract here)
Lu-San Liu, Xue-Mei Shao, Er-Yuan Liang (2006) Climate Signals from Tree Ring Chronologies of the Upper and Lower Treelines in the Dulan Region of the Northeastern Qinghai-Tibetan Plateau, Journal of Integrative Plant Biology 48 (3), 278—285. doi:10.1111/j.1744-7909.2006.00158. (I’ve only looked at the English abstract here
SHEPPARD P. R. (1) ; TARASOV P. E. (2) ; GRAUMLICH L. J. (1) ; HEUSSNER K.-U. (3) ; WAGNER M. (3) ; ÖSTERLE H. (4) ; THOMPSON L. G. (5) ; 2004. Annual precipitation since 515 BC reconstructed from living and fossil juniper growth of northeastern Qinghai Province, China, Climate dynamics, 23,. 869-881 http://www-bprc.mps.ohio-state.edu/Icecore/Abstracts/sheppard_et_al_clim_dyn_2004.pdf
Shao, Xuemei, Lei Huang*, Xiuqi Fang’€ *, *, Lili Wang*, Junbo Wang*, Haifeng Zhu, A Dendroclimatic Study of Qilian Juniper in the northeast Qinghai-Xizang (Tibet) Plateau, http://web.archive.org/web/20031204084631/http://www.igsnrr.ac.cn/files/sxm20020918.pdf downloaded ~2003.
Shao, X.M., Huang, L., Liu, H.B., Liang, E.Y., Fang, X.Q., Wang, L.L., 2004. Reconstruction of precipitation variation from tree rings in recent 1000 years in Delingha, Qinghai. Science in China (Series D) 34, 145—153.
XUEMEI SHAO, ERYUAN LIANG, LEI HUANG AND LILY WANG, A 1437-year Precipitation History From Qilian Juniper in the Northeastern Qinghai-Tibetan Plateau http://www.pages.unibe.ch/products/newsletters/NL2005_2low_res.pdf
Wang Yuxi, Liu Guangyuan, Zhang Xiangong Li Cunfa: 1983, The relationships of tree rings of Qilianshan Juniper and climatic change and glacial activity during the past 1000 years in China, Kexue Tongbao, 28(12):746-750.
Yang Bao, Achim Braeuning, Kathleen R. Johnson, Yafeng Shi, 2002. General characteristics of temperature variation in China during the last two millennia. Geophysical Research Letters 10.1029/2001GL014485
Zhang, Q.-B., Cheng, G., Yao, T., Kang, X. and Huang, J., 2003: A 2,326-year tree-ring record of climate variability on the northeastern Qinghai-Tibetan Plateau. Geophysical Research Letters, Vol. 30(14), 1739, doi: 10.1029/2003GL017425. http://trl.ibcas.ac.cn/download/Zhangqb.Geophysical_Research_Letters.2003.pdf
Zhang et al 2007 A millennium-long tree-ring chronology of Sabina przewalskii on northeastern Qinghai-Tibetan Plateau, Dendrochronlogia 24 http://trl.ibcas.ac.cn/download/Zhangqb.2007.Dendrochronologia.pdf