The Effect of Increased Carbon Dioxide on Water Hydraulics in Trees, and Your Swedish Car.

I think I'll kill 15 minutes saying something useless about xylem hydraulics - the flow of water from tree roots to tree leaves - carbon dioxide, and your car.   If I spent more than 15 minutes, I'm being profligate with time.

One of the things I do here is to mock the "renewable energy will save us" and more specifically, and worse, the "renewable energy will save my car" hypothesis.

I frequently point out that none of the really, really, really, really cool and popular forms of renewable energy, solar, wind, geothermal and biofuels produce one exajoule of the 100 exajoules of energy consumed in the United States, nor one exajoule of the 500 exajoules humanity as a whole consumes.

Guess what?   A nonhydro renewable scheme has reached one exajoule in the US!  Time to stick it to NNadir!

The form of energy in question is biofuels which has reached one exajoule of industrial energy, more or less matching the position it held in the 1940's, when there were still steam engines running on wood.

The 2007 data is in and here it is:

http://www.eia.doe.gov/...

The "Quad" is equal to 1.055 exajoules, and here you see that biofuels produced in 2007 1.018 quads or 1.07 exajoules of energy in the US.

Wow!

We're saved!

We'll ignore for a moment that the total amount of energy produced by biofuels is not as large as the increase in the use of dangerous fossil fuels by pointing out that while natural gas is running away with the atmosphere, oil consumption has fallen slightly.

I'm not a fan of cars, even though I spent part of this week driving 600 miles.   My car got 28.3 miles per gallon on this trip - a little higher than the EPA regulation - but I played a very careful game with the accelerator and the brake to see how much I could coax out of that infernal machine.

In spite of the tremendous biofuels victory, the fuel for the device was over $4.10/gallon.   We'll see the effect too, of Iowa's corn losses too, now that biofuels represent 1/40th of US petroleum consumption.

Although I find the desperate messures to save the automobile silly and although I tire of the "nuclear energy can do nothing about oil" meme (which is equally as silly), I have in the past written about elaborate schemes to save cars and trucks using biofuels that are somewhat more rational than the "still in the holla'" scheme that is so politically popular in every Iowa caucus season.

I have written a few diaries on the subject of grinding up trees to get biofuels like DME: On the Renewable Sources of the Ultra Clean Diesel/LPG/Natural Gas Replacement Fuel

Somewhere I wrote a diary about the Swedish plan to make DME using wood - referencing a huge and elaborate report - but I'm too lazy to look it up right now.

This afternoon, thinking about my infernal car - I had hoped to use Amtrak but it's completely sold out on the Northeast corridor, basically forever - and about a cherry tree that I'd grown from a seed that was mashed into little bits by a falling branch of a neighboring Branford pear - and about my cool gasoline powered chainsaw - and my renewable energy carcinogen fire place and the dangerous fossil fuel spill that occured on my property when I didn't use a funnel while pouring gas in the chainsaw, and all of this stuff like this, like the external cost of the wood I'm going to burn next winter...

I wondered...

How much carbon dioxide does a tree remove from the atmosphere exactly?

Part of the reason involved the fact that I was stuck in a hotel last night, ran out of stuff to read, and found myself watching "Frontline" after "Nova" - the latter funded by Exxon Mobil, your environmentally friendly climate change denying corporation.

According to Frontline, there seems to be a problem - let's not get into the details lest we offend Exxon - with the glaciers in the Himalayas.   It is suspected that these problems might involve a feedback loop, since when water stops flowing from the Himilayas stuff that takes carbon dioxide out of the air - they're called "plants" might die, removing less carbon dioxide.   One of the claims on "Frontline" was made by a person who suggested that people think that all humanity has to do is to adjust to a new - hotter - climate, and they'll be OK.   That might not be the case the scientist suggested.   We might have to deal with a continuously dynamic climate - one that is not the same from year to year - but is continuously changing.   That, he claimed, would be a far more difficult problem.

It's kind of arcane.   You don't need to know.   You don't want to know.

So when I got home I decided to leaf through - get it "leaf through?" - the journal Tree Physiology.

This is a really cool journal, and it has lots and lots and lots and lots and lots of stuff about trees and - isn't this a coincidence since I was just hearing about it on television - carbon dioxide.

Apparently trees - who knew? - can get screwed up by carbon dioxide - making the plan to make motor fuels from trees somewhat problematic maybe could be possibly in a manner of speaking.

Here for instance is an excerpt from one of the articles I scanned today:

Water relations of a tree depend on its hydraulic properties, i.e., the size, distribution and morphology of water-conducting xylem elements; Tyree and Zimmermann 2002). Water flow generally follows the Hagen-Poiseuille law (Schulz and Matthews 1993, Lovisolo and Schubert 1998, Schulze et al. 2005). When trees grow in particular environmental conditions, water flow within the tree, and the tree's hydraulic structure, acclimate to the environment (Larcher 2003a, Schulze et al. 2005, Holste et al. 2006). For example, a leaf that develops in direct sunlight (sun leaf) has a higher transpiration rate and stomatal conductance (gs) than a leaf grown in shade (shade leaf; Sellin and Kupper 2005a, 2005b). Schultz and Matthews (1993) showed that petioles in grapevines exhibited structural or anatomical changes according to light conditions.

The continuing increase in atmospheric CO2 concentration ([CO2]) has raised interest in determining how trees respond tothis environmental change. Our study aimed to determine if a significant increase in [CO2] changes water flow in a woody plant, leading to acclimation in hydraulic structure. Many studies have shown that leaf transpiration rate and gs decrease in response to elevated [CO2] (e.g., Drake et al. 1997, Saxe et al. 1998, Urban 2003). However, some hydraulic parameters, such as hydraulic conductance and conductivity, do not invariably decrease (Heath et al. 1997, Bunce and Ziska 1998, Tognetti et al. 2000, Wullschleger et al. 2002, Urban 2003). Some reports indicate that elevated [CO2] causes changes in vessel element or tracheid size (Yazaki et al. 2001, Ceulemans et al. 2002), but others found no such effect (Kaakinen et al. 2004, Yazaki et al. 2004). Elevated [CO2] increases the number of leaves per plant (Norby et al. 1999, Poorter and Navas 2003), changing the extent of self-shading per shoot or per individual plant (Oikawa 1986, Li et al. 2003). This means that transpiration per shoot or per plant is determined, not only by the direct effect of high [CO2], but also by its ndirect effects on plant development and form. As a result, transpiration by individual plants does not necessarily decrease with increased [CO2] despite a reduction in gs (Pospíšilová and Èatský 1999)...

...blah...blah...blah..."sciency" stuff...blah...blah...

Conclusions:

Changes in hydraulic structure can be brought about by long-term changes in water flow caused by environmental change. Yazaki et al. (2005) reported that changes in cambial activity in response to elevated [CO2] affect xylem structure. Effects of elevated [CO2] on cambial activity may represent a key early step in the physiological mechanism(s) underlying changes in hydraulic structure. In conclusion, plants grown at high [CO2] generally show decreases in gs or an increase in water-use efficiency, indicating acclimation of hydraulic structure. We studied sun leaves and shade leaves separately and found data consistent with acclimation of hydraulic structure to elevated [CO2].

TAKAYOSHI KOIKE et al, Tree Physiology 28, 287–295 (2008).

Wait a second...

This is good news!   We got to say "more efficiently."

We're saved!!!!

Oh happy day!  And you were worried that carbon dioxide might cause a problem with your plan to grind up trees to fuel your car!

We're saved!!!!

More carbon dioxide is good for water efficiency, and as we all know, efficiency can save our cars which is a good thing, since we will all die without cars.