Comments on: Surprise: Leaves Maintain Temperature, new findings may put dendroclimatology as metric of past temperature into question

By: Synyster

Synyster — Thu, 30 Oct 2008 14:08:33 +0000

well, i was just searching about leaves internal temperature then this page came out. jst wnna check cos this thing came out during the November biology o-level exam few days ago. i totally don’t know about the constant internal temperature thingy. it’s not even on the subject’s syllabus. crap. so i panicked at that time. but it looks like my answer was correct then. i mentioned about the evaporation and others. so yeah. whee~ ahaha.

By: Celebrity Paycut - Encouraging celebrities all over the world to save us from global warming by taking a paycut.

Mon, 07 Jul 2008 16:31:59 +0000

[...] links today to Anthony Watts’ excellent blog ‘Watts Up With that?’. The first, highlights new research with potentially huge implications for how past climates are measured, [...]

By: The Greenhousers–At Least They Have Pluck

The Greenhousers–At Least They Have Pluck — Sun, 22 Jun 2008 02:59:16 +0000

[...] Tree Ring theory upon which Mann relied was proven wrong, as tree leaves maintain a constant internal temperature of [...]

By: poetSam

poetSam — Tue, 17 Jun 2008 14:13:42 +0000

Takes bow, falls over :)

By: J.Hansford.

J.Hansford. — Tue, 17 Jun 2008 04:36:05 +0000

Poet sam…. LoL…

By: David Segesta

David Segesta — Mon, 16 Jun 2008 15:31:01 +0000

Anthony, I think the outdoor air temp right now is probably quite a bit hotter than 21.4C in your neck of the woods. So you should be able to read that difference easily. My efforts at feeling leaves was rather unproductive. It seems my fingers are not calibrated that accurately. So I await the results of your tests with bated breath …or is it bad breath? Well whatever.

I guess you’ll have to wait until winter to see if the leaves can heat themselves.

By: Gary Gulrud

Gary Gulrud — Mon, 16 Jun 2008 14:19:03 +0000

Adding to Mike D.:

Most dendro series include trees as young as 60 years, that can be ‘uniquely fit’ into the chronology at a number of places.

Most are proprietary and subject only to review by trusted experts. Wegman showed the interdependancies of such networks to be imprudent.

Keenan at ‘informath’ has a paper or two on 14C dating that also point up the very limited geographic scope of the dendro series when used to ‘calibrate’ other proxies.

Better than SWAG, but unrepeatably so.

By: kim

kim — Mon, 16 Jun 2008 13:55:15 +0000

What happens at night? Do the leaves assume ambient temperature?
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By: poetSam

poetSam — Mon, 16 Jun 2008 04:12:01 +0000

Leaves that are green are in the air seen
leaves that are brown are oft on the ground.
But leaves that are cool
seems the general rule.

By: Evan Jones

Evan Jones — Mon, 16 Jun 2008 02:38:23 +0000

I’m going to go out in the back yard and feel some leaves. :-)

My neighbors are going to think I’m crazy.

Better watch out or you could be the next star on YouTube come Monday.

By: Mike Bryant

Mike Bryant — Mon, 16 Jun 2008 00:14:01 +0000

I’m gonna put a fan in the branches of my pecan tree and point it at my patio…

By: Pamela Gray

Pamela Gray — Sun, 15 Jun 2008 23:51:23 +0000

To duplicate this experiment, you would need the same 39 species at the same altitudes, measured in like manner. Doing less may increase your odds of hitting an odd data point that may not match the conclusions. I realize what I am saying is that anecdotal evidence proves nothing. Which I agree with, and you never use anecdotal evidence after your initial observation of said anecdote to prove or disprove the hypothesis.

By: David Segesta

David Segesta — Sun, 15 Jun 2008 23:16:35 +0000

This is certainly an unexpected result. A tree leaf has a very high area to volume ratio. That’s the way you would design something if you wanted it to transfer heat to or from the air, like a cooling fin. Its not the ideal shape for maintaining a temperature that is different from the air. Also, unlike the polar bear the leaf does not have a coat of insulating fur.

Anthony you should be able to test this with your infra-red camera. If you get the same temperature reading then maybe I’ll have to change my opinion. In the mean time I’m going to go out in the back yard and feel some leaves.
:-)

My neighbors are going to think I’m crazy.

REPLY: Way ahead of you. (the camera, not the crazy behavior)

By: Pamela Gray

Pamela Gray — Sun, 15 Jun 2008 23:10:11 +0000

Mike, I am out in the woods regularly at logging sites (my boyfriend works on broken equipment). I love your post about all the things that can affect tree rings. I always study the tree rings when I am at logging sites. You can easily see what you are talking about by looking at the cut ends in each stack. There are similarities there that are not necessarily present in the next stack at another logging site. Older sites, cherry picked sites, clear cuts, young sites, lower vs higher elevations, fire, dryer location, wetter location, shade, sun, etc, can be deduced by looking at the tree rings at each site. Fascinating.

By: retired engineer

retired engineer — Sat, 14 Jun 2008 22:49:50 +0000

“I think that I shall never see
a poem so lovely as a tree”

With apologies to both poetSam and Kilmer

By: BUCKO36

BUCKO36 — Sat, 14 Jun 2008 19:17:17 +0000

This discussion brings a whole new meaning to the “old” song. “In the shade of the old Apple tree”.

Can a tree now be considered a “natural” air conditioner, in addition to providing shade when it is hot out?????

Just wondering!!!!!!

By: Mike Bryant

Mike Bryant — Sat, 14 Jun 2008 15:47:57 +0000

This bit of knowledge is so incredible. I had to go touch a leaf here in 85 degree south Texas…. cool….

By: leebert

leebert — Sat, 14 Jun 2008 15:05:06 +0000

It’s as though they had never heard of evapo-transpirative cooling!

It’s interesting b/c I read a paper a while ago on the use of light oxygen proxies to describe the amt of water vapor locked up in the more-arid ice ages. The release of water vapor tracked more consistently with the paleo temperature record than CO2 levels.

http://i29.tinypic.com/28iyro8.jpg
( superimposition of the light oxygen chart over the vostok chart).

By: beng

beng — Sat, 14 Jun 2008 13:43:59 +0000

Believe it or not, I’ve wondered about this recently while thinking about the effect of solar radiation on solid surfaces. Surfaces generally get “hot” while exposed to the sun, unless they’re white or reflective. Leaves (including grass-blades) aren’t either one, so I wondered why they didn’t get hot. As an engineer, I figured offhand that it had to be water evaporation — a wet sponge in the sun (even if colored black) won’t get hot either, until it dries out.

This helps explain why a forested area, even w/its low albedo (dark) surface, still remained much cooler than surrounding open/urban areas which usually have higher albedo. When I lived in a dense forest during the worst heat-waves the air temp could be 10F deg cooler than nearby urban areas — say 90F compared to 100F.

Ben Flurie

By: poetSam

poetSam — Sat, 14 Jun 2008 13:15:15 +0000

J. Hansford

My poem though it rhyme
is not without reason.
If Pam I not like
I would not be teasing.

Oh, well. They can’t all be good.