Comments on: Bristlecone Pines: Treemometers or rain gauges ?

By: Evan Jones

Evan Jones — Sun, 23 Mar 2008 00:58:21 +0000

According to Liebig’s Law, might it be prudent instead to use trees located in the cold climates where heat, not water would be the limiting factor?

BTW Does anybody of you know the percentage in the MBH98 graph which is taken The Bristlecone Pines Trees?

Per: It’s worse than you think. The 2005 paper, and on Mac’s site (ClimateAudit), it is claimed that the BCP samples are weighted 390 times as much as the others.

By: Jeff Alberts

Jeff Alberts — Sat, 22 Mar 2008 18:05:05 +0000

One gets the feeling that examining tree rings is about as scientifically valid as examining the entrails of goats.

Only if those goats are grazing near Bristlecone Pines. ;)

By: Jeff

Jeff — Sat, 22 Mar 2008 13:28:25 +0000

One gets the feeling that examining tree rings is about as scientifically valid as examining the entrails of goats.

By: Jeff Alberts

Jeff Alberts — Fri, 21 Mar 2008 22:26:55 +0000

Sorry, to differ, Steve. But I live very west of the Cascades, and my grass is always brown in the summer, green in the winter. The year after I moved out here (2002) we went 88 days without rain on Whidbey Island, and that wasn’t very out of the ordinary. It may be different closer to the Cascades where clouds coming in from the west and north pile up against the mountains and produce more precip, but along the I-5 corridor, we don’t get a lot of rain in the summer. Like I mentioned before, Dallas, NYC, just about any major city gets more ran than Seattle annually.

By: Jim Arndt

Jim Arndt — Fri, 21 Mar 2008 18:56:47 +0000

Hi,

Sorry but this is a little OT. Seeing Tamino like the BCP for his PCA. I is best described like this.

By: SteveSadlov

SteveSadlov — Fri, 21 Mar 2008 17:12:39 +0000

The excluded PNW sites are in various places. Some of them are west of the Cascades, and therefore, do not experience a very pronounced lack of summer moisture. Of course, believe it or not, east of the Cascades, in many years, the SW monsoon, while not reaching the area per se, injects enough moisture into N Nevada / the southern Columbia Plateau, that there is enough available for subsequent local convective events. So, even east of the Cascades, there is at least an even chance in any given year that summer moisture may be enough to prevent slowing of growth owing to drought stress.

One site I like is on Vancouver Island. Absolutely no moisture limitation. If there are treemometers anywhere, they are in the Marine West Coast climate zones.

By: Jeff Alberts

Jeff Alberts — Fri, 21 Mar 2008 15:18:51 +0000

The excluded sites seem to be mostly in the very wet Pacific Northwest.
It would be interesting to see what would happen if they were included.
Even better, to see what would happen if they were the only data.
It is good to know the size of the cherry picking effect.

The PNW isn’t that wet. Seattle gets less annual rainfall than Dallas and New York City. It’s just that it tends to be an all-day, slow drizzle affair when it does happen. I’m sure there are some parts of the PNW that are very wet, but it’s not everywhere up here.

By: steven mosher

steven mosher — Fri, 21 Mar 2008 12:27:19 +0000

i pointed this out before to stmc. look at 1850. now google drought 1850

By: bob

bob — Fri, 21 Mar 2008 09:19:00 +0000

Sometimes very simple things have a vast impact on science. Therefore SteveMcIntyre deserves a Nobel Prize.

By: Chuck Bradley

Chuck Bradley — Fri, 21 Mar 2008 05:13:33 +0000

The excluded sites seem to be mostly in the very wet Pacific Northwest.
It would be interesting to see what would happen if they were included.
Even better, to see what would happen if they were the only data.
It is good to know the size of the cherry picking effect.

By: ferris

ferris — Fri, 21 Mar 2008 04:08:12 +0000

Hey, I just came across this thread. I’ve been commenting over at Climate Audit on this very subject. Between my comments over there and finding this thread, I came across some information which everyone might find interesting. It’s a discussion on BCP ring widths by Harold C. Fritts. The paper can be found here: http://tree.ltrr.arizona.edu/~hal/tancient.pdf

Enjoy!

By: Bill Illis

Bill Illis — Fri, 21 Mar 2008 01:59:39 +0000

Just look at the picture of those trees. They are typical of the bristlecone pine trees we are talking about.

How can you possibly use a core sample to detect any kind of signal from that. Half the tree is dead at any one time and there is no bark on it on the other half of it.

The tree might be long-lived but any particular ring taken from a core drilled through any particular angle on the tree cannot tell you what the temperature was in 1716. Half the tree was dead in 1716, an maybe one little section was growing rapidly while nearby sections were trying to recover from insects in 1715.

Great tree, but the overlapping jumble of live and dead sections are not the “sweetspot’ for temperatures over the past 1,000 years. Mann picked them to use as his heaviest weighted data source because the jumbled mess of data produced can easily be manipulated.

By: Mike Borgelt

Mike Borgelt — Thu, 20 Mar 2008 22:08:25 +0000

My exposure to tree rings was back in 76-77 when a visiting tree growth ring expert from the US gave a seminar on the water flows in the Colorado river. He thought that in the Colorado catchment tree growth rings going back 400 years were an excellent paleo rain gauge. Didn’t say anything about temperatures.

By: SteveSadlov

SteveSadlov — Thu, 20 Mar 2008 18:04:56 +0000

Sorry, forgot to mention, storms coming from the W or SW (typical of El Nino) drop a lot of precip W of the Sierra, and on the W Slope of the Sierra. But east of the Sierra, their impact is limited. Only the strongest El Ninos will result in much moisture making it past the crest. The best “approach route” for snow bearing systems, in the White – Inyos is from the north. Which is typical of La Nina or neutral.

By: SteveSadlov

SteveSadlov — Thu, 20 Mar 2008 18:02:21 +0000

It’s not completely unconnected to ENSO, but, only weakly connected. Years with the best late season snow pack can be either ones with a very strong El Nino (rare, see below) or ones where moisture got delivered late, down from the north (typically but not always La Nina years). The secondary moisture control, summer monsoon, is so late in the season (typically after late July) that it’s almost too late. Plus. monsoon T-storms are hit or miss. Also, if the monsoon points west or, north, instead of NW, it may miss this area completely. Put is all together, and the Mannian notion of an indirect correlation, with greater precip driven growth being teleconnected to a general trend of more dominant El Nino ergo “global warm period / trend” sort of falls apart. If there is any teleconnection it would probably be with bad winters in the intermountain West and Northern High Plains. BTW – this year is such a year and snow pack is good in the White / Inyo Mountains.