Category Archives: bristlecones

Sheep Mountain Update

Several weeks ago,  a new article (open access) on Sheep Mountain (Salzer et al 2014 , Env Res Lett) was published, based on updated (to 2009) sampling at Sheep Mountain. One of the longstanding Climate Audit challenges to the paleoclimate community, dating back to the earliest CA posts, was to demonstrate out-of-sample validity of proxy reconstructions, […]

Salzer et al 2009 – A First Look

Salzer, Hughes et al (PNAS 2009) is in the news. It reports that “unprecedented” high-altitude bristlecone growth, citing increased growth at Sheep Mountain, Mount Washington and Pearl Peak, but especially Sheep Mountain. pdf PNAS SI Salzer SI CA readers are obviously familiar not just with bristlecones, but with Sheep Mountain. As pointed out in the […]

8500-Year Old Tree Found in Sweden

A news report says that the oldest living tree has been found on the Sweden-Norway border. The report comes from Leif Kullman, a prominent Swedish paleo-scientist. The story says: Prof Leif Kullman at Umeå University and colleagues found a cluster of around 20 spruces that are over 8,000 years old. The oldest tree, in Fulu […]

More Mystery at Sheep Mountain

The Sheep Mountain CA bristlecone site is the most important proxy in MBH and the MBH98 reconstruction actually doesn’t differ very much from the Sheep Mountain tree ring chronology (other than it ends in 1980 at pretty much the peak of the Sheep Mt chronology and doesn’t include the downtick in the 1980s.) Various efforts […]

A New Divergence Problem

A reader has drawn to my attention that chapter 3 of the Ababneh Thesis, disussed previously at CA here here and here was published in Quaternary International (in Sept 2007 just prior to my initial post.) Since I did not refer to this peer reviewed publication in my earlier review, I wish to update these […]

Malcolm Hughes and the Witness Protection Program

Malcolm Hughes coauthor Matthew Salzer) made a presentation entitled “Twentieth Century Bristlecone Pine Tree Rings near Upper Tree Limit Wider than in Recent Millennia”. This included a report on Sheep Mountain. He showed a picture of Matthew Salzer on Sheep Mountain and praised his work. He said that there was no difference between strip bark […]

realclimate on Loehle

RealClimate has a good discussion of problems with Loehle 2007: link, linking to JEG’s discussion but not to discussion here. Update: Luboš has a discussion here. In some cases, RC non-linking to climateaudit is mere pettiness, but, in this particular case, they cite information on Loehle that was initially made available at climateaudit. In this […]

Almagre Data

A couple of days ago, I received the Almagre measurement data from the excellent dendrochronological lab at the Univesity of Guelph. I’ve posted the measurement data online in two files (as I received them): crossdated and uncrossdated. There are 41 cores that have been crossdated and 20 cores are not crossdated. These files are as […]

The Sheep Mountain Update

This post contains an important calculation, which will affect the many multiproxy studies in which Graybill bristlecone chronologies impact results either directly or via Mann’s PC1. Hans Erren has digitized the data from the Ababneh Thesis. In Figure 1 below, I’ve shown the difference between the updated Sheep Mountain chronology and the Graybill chronology. The […]

Hughes and the Ababneh Thesis

I’ve had a few requests to comment on Eli Rabett’s recent post, observing that he was unable to observe a Medieval Warm Period in the bristlecone chronology reported in Salzer and Hughes 2006. Looking at the tree ring index one can clearly see many large eruptions, the little ice age, but no European Warm Period, […]