Category Archives: bristlecones

Review of Osborn and Briffa [2006]

Osborn and Briffa [2006] , published today in Science, cannot be considered as an “independent” validation of Hockey Stick climate theories, because it simply re-cycles 14 proxies, some of them very questionable, which have been repeatedly used in other “Hockey Team” studies, including, remarkably, 2 separate uses of the controversial bristlecone/foxtail tree ring data. Also […]

New York Times on Bristlecones

I’ve been working away at our reply to Ammann and Wahl so I’m a little behind in blogging. One of our readers drew my attention to a discussion in the New York Times involving our favorite bristlecone pines. Kammerer et al. [J. Im. Gen. 2006] report the extension of human lifespan to 969 years following […]

Cutting Down the Oldest Living Tree in the World

Many Americans of a certain age will recall an American radio commentator, called Paul Harvey, who ran ironic commentaries entitled "The End of the Story". They were short segments leading you to expect one answer and Harvey’s closing comment explaining what happened would reverse the field altogether. I once heard a commentary on dendrochronology, in […]

Upper and Lower Bristlecone Sites

A while ago, I discussed the very interesting study by Naurzbaev et al [2004] (co-author Hughes), which calculated growth curves at 34 larch sites in a meridional transect from 55 to 72 N (at a longitude of about 90-100E) and 23 larch sites along an altitudinal transect from 1120 to 2350 m around Tuva (~ […]

Another Bristlecone/Foxtail Site: Timber Gap CA

After a couple of bitchy posts about Ritson and Huybers, I’d like to do something a little more cheerful. Here’s some information that I’ve collected about Timber Gap Upper (ca529) and Timber Gap Lower (ca532), two Graybill foxtail pine sites that were important components of the MBH98 PC1 and have been used elsewhere. I’ve identified […]

Upside-Down Quadratic Proxy Response

David Stockwell has suggested a discussion of nonlinear responses of tree growth to temperature. I’ve summarized here some observations which I’ve seen about bristlecones, limber pine, cedars and spruce – all showing an upside-down U-shaped response to temperature. The implications of this type of relationship for the multiproxy project of attempting to reconstruct past temperatures […]

Graybill and Funkhouser [1993] on Bristlecones

I have recently located a copy of Graybill and Funkhouser [1993], Dendroclimatic Reconstructions during the past millennium in the southern Sierra Nevada and Owens Valley, California, which has been very hard to find. This appears to be Graybill’s last publication before he died. A detailed excerpt follows. Some key quotes: Unfortunately the chronologies from the […]

Lamarche on Treelines #2

Here is Lamarche’s diagram of altitudes at the key bristlecone sites of Sheep Mountain and Campito Mountain (as noted below, when wood erosion is allosed for, the post-MWP decline is placed after 1500.)

Lamarche [1973] on Treelines #1

Valmore Lamarche was perhaps the first person to suggest that temperature information could be extracted from bristlecone pine information and his early publications are often referenced. Lamarche et al. [1984] (with Fritts, Graybill and Rose) first postulated CO2 fertilization. As you know, I’m increasingly interested in changes in treeline elevation as a "low-frequency proxy". It […]

Bristlecone dC13

I’ve recently run across an article on changing water use efficiency in bristlecones, which pretty much put the nail in the coffin on any lingering ideas that 20th century bristlecone ring widths might be a temperature proxy. Tang et al. [1999], "The dC13 of tree rings in full-bark and strip-bark bristlecone pines in the White […]