Tree leaves across North America share same temperature

by rpshen | June 11, 2008 at 02:02 pm

3603 views | 6 Recommendations | 26 comments

While we are not surprised that two species of animals share the same internal temperature regardless of their habitats, but the fact that tree leaf species across North America all share a relatively constant temperature is quite amazing. In fact, the temperature of tree leaves provide much insight into other natural phenomenon such as weather.

The temperature inside a healthy, photosynthesizing tree leaf is affected less by outside environmental temperature than originally believed, according to new research from biologists at the University of Pennsylvania. Surveying 39 tree species ranging in location from subtropical to boreal climates, researchers found a nearly constant temperature in tree leaves. These findings provide new understanding of how tree branches and leaves maintain a homeostatic temperature considered ideal for photosynthesis and suggests that plant physiology and ecology are important factors to consider as biologists tap trees to investigate climate change.

Tree photosynthesis, according to the study, most likely occurs when leaf temperatures are about 21°C, with latitude or average growing-season temperature playing little, if any, role. This homeostasis of leaf temperature means that in colder climates leaf temperatures are elevated and in warmer climates tree leaves cool to reach optimal conditions for photosynthesis. Therefore, methods that assume leaf temperature is fixed to ambient air require new consideration.

Leaf temperature, cooled by the physiological and morphological techniques of evaporation, leaf angle or reflection and heated by a decrease in evaporation and an increase in the number of leaves per branch, can now be considered adaptations towards achieving homeostasis. Researchers do not suggest that tree canopies maintain a constant temperature through a day or a season, but rather that this ideal temperature is a long-term target value.

The study also presents a new hypothesis for why certain trees grow in certain climates and provides a new theory for how and why trees in the north will suffer from global warming, by overheating due to the mechanisms they have evolved to keep their leaves warm.

In addition, weather-forecasting models rely on accurate estimates of surface-water evaporation, much of which comes from tree leaves. Knowing the temperature of these leaves is crucial to an accurate prediction of future climate scenarios.

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baldybikerboy

at 01:31 on June 12th, 2008

Leaf of Willow tree - Leeds UK

baldybikerboy has contributed a photo to this story.

windysam

at 05:50 on June 12th, 2008

New leaves of Peepal Tree taken in a village near Pune, Maharashtra, India. The new leaves are pinkish in colour and later on turn green as they grow.

windysam has contributed a photo to this story.

Daisy.Sue

at 06:23 on June 12th, 2008

Was taking a walk one hot, humid Sunday when I saw this low growing plant under large pine trees in someone's yard, in Putnam County, Carmel,NY. It looked different and very cool where it was growing.
6-08-08

Daisy.Sue has contributed a photo to this story.

jo_ko

at 06:42 on June 12th, 2008

taken in Huntersville, North Carolina. Fall 2007.

jo_ko has contributed a photo to this story.

jfully

at 07:38 on June 12th, 2008

"It was a dark and stormy night,...."
Well, not really, just a hot and sticky night in Somerville...but the leaves were amazing!

jfully has contributed a photo to this story.

caidid

at 07:48 on June 12th, 2008

Taken in Boston, MA on the campus of Boson University on a spectacularly beautiful day in September of 2007.

caidid has contributed a photo to this story.

negFoto

at 08:06 on June 12th, 2008

Gardenia flower. Taken in my yard, I just love the fragrance.

I find this story very fascinating. Thank you for inviting me to be part of it.

Ricardo Cordeiro

at 09:32 on June 12th, 2008

I was surprised to see a japanese-style garden hidden in the middle of a park on Sintra (Portugal). This photo is from one of the many ancient-looking bonsais I saw there.

Ricardo Cordeiro has contributed a photo to this story.

Madeline Nicole

at 10:12 on June 12th, 2008

Mountain Ash Tree in Calgary Alberta, Fall 2007.

Madeline Nicole has contributed a photo to this story.

yarnmaven

at 12:29 on June 12th, 2008

I believe this to be a mulberry tree, but am unable to determine whether it is a white, Texas or other species. It grows on my property in Bastrop County near Austin, Texas beside an ephemeral pond.

yarnmaven has contributed a photo to this story.

dichohecho

at 12:50 on June 12th, 2008

My leaves are in Somerset, UK

not North America :)

tonyrs

at 13:17 on June 12th, 2008

This sapling is growing well and is a third generation Rowan grown from seed from my mother & father's tree. I have 10 others and hope to plant them back into the wild in a year or so.

tonyrs has contributed a photo to this story.

futureprogress

flagged this story as Good Stuff

at 14:13 on June 12th, 2008

...very interesting indeed.

zeppelin158

at 14:16 on June 12th, 2008

My picture was taken on a hot day when it was nearly 100 degrees. Taken in Lansdale, PA. Thank you for using my material, please come back for more when you need it. Anything to get my work out there. :)

zeppelin158 has contributed a photo to this story.

blackdiamondimages

at 14:41 on June 12th, 2008

My images of Meterosideros excelsa - Pōhutukawa were taken in the North Island of New Zealand.

pianoplr12341

at 15:42 on June 12th, 2008

This photograph was taken on a local golf coarse which just happens to be set out throughout the neighborhood, including our backyard. It is of a tree by a stream full of wild berries in Ralaigh, North Carolina. The picture is taken in the view point of someone looking towards the sky at the many branches of a tree of an unknown species (to me anyway).

pianoplr12341 has contributed a photo to this story.

Kellett School

at 16:33 on June 12th, 2008

Images taken by Y7 student during field trip to Kota Kinabalu, Borneo

Kellett School has contributed a photo to this story.

akakibby

at 18:07 on June 12th, 2008

This tree was in Asian section of the WDW Animal Kingdom park in Orlando Florida USA. I just liked the way the colors of the leaves contrasted against the bark of the tree, and lighting was good. If have not been to this park, it is a treasure trove of many many tropical plants in addition to wonderful animals in the park. It is my favorite of the 4 Disney parks in Florida.

akakibby has contributed a photo to this story.

hazrulabdulhalim

at 19:06 on June 12th, 2008

Ladybird and pumpkins' leaves - Terengganu, Malaysia.

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nukemdomis

flagged this story as Good Stuff

at 19:17 on June 12th, 2008

Awesome story rpshen,

Out here in Las Vegas, the trees that grow here do very well in the hot weather (100 F) so suffering from global warming shouldn't affect these trees for a long time.

I like this story. It's good stuff.

Paul Conneally

flagged this story as Good Stuff

at 21:49 on June 12th, 2008

rpshen, I like this story. It's good stuff.

Plants are more complex than many like to think... thats whiy they were here before us and will be here after us too...

Aussie Jules

at 22:01 on June 12th, 2008

Liquid Amber.
Victoria, Australia.

Aussie Jules has contributed a photo to this story.

olushka

at 02:00 on June 13th, 2008

This picture was taken in Devonport - the best part of Auckland New Zealand. Autumnt, golden leaves, an old stile villa behind the tree, romantic time.

olushka has contributed a photo to this story.