How do Trees Really lift Water to their Leaves?

BC:
"1. Yes, no-one said different."

Well, actually I did say differently.

You start with a gram of sap. It loses a tenth of a gram of water by transpiration and gains a tenth of a gram of water drawn up from the roots.
You have exactly the same thing as you started with so the density is the same as it was.

Anyway, since Andrew is quite passionate in his refusal to even try to show us some numbers I think it's fair to assume that he knows that wouldn't support his point of view.
Until I see him prove otherwise I don't see anything changing my opinion on the matter.

Rosy:

Yeah, alright BC, you have a point. Sorry.

I think there's a (very sloppy) argument (or isn't there?) that some of the water drawn up the xylem (as part of a less-dense) solution then becomes part of a (more dense) solution in the phloem, so in that sense a solution gains density (if you ignore the whole transport into/out of cells thing that has to happen at the top, which you can't really).

And you're probably right about Andrew too, not sure why I bother... but somehow I keep on coming back in the hope some day he'll catch on.

I keep coming back also in the hope that someday you will all catch on!

Those pictures of varicose veins resolving by tilting a bed the opposite way to that recommended by the medical profession is not unrelated to this discovery as has been suggested in the past.

I tilted the bed in the first place to test if a flow and return in the body was present. If it was then a swollen vein would reduce in size. Precisely what happened and is happening to many people.

Yet conveniently ignored by people who should know better!

Very difficult to ask a tree if gravity is having an affect. But very easy to ask a person to lay on an angle and observe the changes!

You may not like the fact that someone outside of academia has delivered a profound discovery and frankly I couldn’t give two hoots what belief based system you adhere to.

The experiments shown on Youtube speak volumes more than an imagined impossible leaf based pull on a 100 plus meter Californian Redwood.

Show me the numbers that support this absurd belief?

Better still take a look at what the students think about it: www.thestudentroom.co.uk/showthread.php?t=599353

The cohesion tension hypothesis relies on a continuous bead of water to support a column and the evaporation at the top of the column can not only support the fluid but can pull it up the trunk and release it into the air.

But we know that cavitation takes place all of the time and that any break in the bead of the imagined cohesion tension generated by a flimsy leaf flapping around in the breeze would render the whole process redundant. Yet the tree appears to not be affected by the constant cavitations, which can be heard cracking with a standard stethoscope. But that’s accepted and to be expected in a belief -based system.

You can’t ignore this fact!


The following relates to the cohesion tension hypothesis.
4e.plantphys.net/article.php?ch=&id=99

Rosy:
Andrew

If you got over your puerile inverse-snobbery for just long enough to give our criticisms of your system serious consideration, you would do one of two things. Either you would strengthen your argument immeasurably, or alternatively (and I grant you I think it's more likely), you'd realise that your model is untenable and be able to go away and refine it/not spend the rest of your life beating your head against the internet.

If you don't address this very specific question, you will be a fool in ways that have nothing to do with academic qualifications one way or another, but everything to do with blind arrogance.

But we know that cavitation takes place all of the time and that any break in the bead of the imagined cohesion tension generated by a flimsy leaf flapping around in the breeze would render the whole process redundant. Yet the tree appears to not be affected by the constant cavitations, which can be heard cracking with a standard stethoscope. But that’s accepted and to be expected in a belief -based system.

Bunk. Trees grow outward, too, you know. They grow new xylem and phloem tissue which is filled with fluid as the cells grow. Sure some of them break, that's why new ones are required.
Plus of course you've shown (bully for you) that even with an enormous diameter tube (relative to a xylem) it is perfectly possible to raise a column of water above 10 m (not an equilibrium system, but then life has very few equilibrium systems), and given a much finer column and therefore very different surface behaviour between the xylem fluid and the inner surface of the xylem, your "argument from incredulity" doesn't wash there.

Just because you don't believe it can happen, doesn't mean it doesn't.
On the other hand if the energy accounting doesn't work out you better have a pretty damn good explanation because you've just declared all trees to be perpetual motion machines on a grand scale.

Your inclined bed theory has nothing to do with trees and might stand a better chance of not "being ignored by people who should know better" if you made at least some effort not to come across as a fool. After all, the first google result for "Andrew K Fletcher" (and therefore the first thing someone wanting to find out more about this person who's sent them information about his new theory for solving all of medicine), is your Naked Scientist Forum profile. Which will bring them straight here. The majority of people in the category of "people who should know better" are likely to feel much as I do about your total refusal to interact with our very specific criticisms of your pet theory.

The cavitations repair themselves, cavitations are taking place all of the time and emit loud cracking sounds. This does not result in the collapse of the circulation in the tree and this is where the problem with the cohesion tension hypothesis lies.

Have you any idea of how much pressure would be required to support the columns of water in tall trees using the cohesion T model? Do you not think that the leaves would literally become inverted under such immense tension or even sucked down the trees vessels for that matter?

Pete Scholander and Ted Hammel hit the nail on the head when they made the pressure bomb and began recording pressures far above those proposed and required by the CTT.

So ask yourself if this imaginary impressive tension is not present in tall trees how on earth are they able to conform with the rest of the theory?

Can you not see how absurd it is to propose that leaves can suck up water from the roots no matter how it is wrapped up?

@BenV
Ben let us look at those maths in the Cohesion tension hypothesis first.
4e.plantphys.net/article.php?ch=&id=99
The application of the Ohm′s law to sap flow encompasses many phenomena (heat transfer, water transfer in soil, Darcy law, first diffusion law, etc.) and, it is therefore independent of the underlying physical mechanisms and the nature of moving fluid. For example, the electrical approach does not address whether sap is under tension or pressure. For this reason, the description of sap flow by Ohm′s is rather "phenomenological".

Had to look this word up: en.wikipedia.org/wiki/Phenomenology_%28science%29
Phenomenology in physical sciences

There are cases in physics when it is not possible to derive a theory for describing observed results from the known first principles (such as Newton's laws of motion or Maxwell's equations of electromagnetism). There may be several reasons for this. For example, the underlying theory is not yet discovered, or the mathematics to describe the observations is too complex. In these cases sometimes simple algebraic expressions may be used to model the observations or experimental results. The algebraic model is then used to make predictions about the results of other observations or experiments. If the predictions made by the algebraic model are sufficiently accurate, they are often adopted by the scientific community despite the fact that the algebraic expressions themselves cannot be (or have not yet been) derived from the fundamental theory of that domain of knowledge.

The boundaries between theory and phenomenology, and between phenomenology and experiment, are fuzzy. Some philosophers of science, and in particular Nancy Cartwright argue that any fundamental laws of Nature are merely phenomenological generalizations.

Rosy:
You keep on about how we're tied to the current explanations. Some of the other people you're talking to may be, I'm not. Indeed, I have little knowledge of how biologists (or indeed anyone else) explains exactly how trees work.

However, what I am interested in is the basic physics of this situation. You keep on, and on, and on, about how your macro experiments support your micro interpretations. All I'm saying is that they don't. Your experiments (certainly the ones I've seen), don't show diddly-squat of any relevence.

As you rightly say, what we "know" about science is quantified interpretation of experimentaly data and, often, there are gaps in exactly how far we can explain the origins of those quantitative relationships between this, that, and the other thing. And certainly much (or argualbly all) of biology falls into that category. On the other hand one of the most (possibly the most) tried, tested, and still undefeated bits of science is thermodynamics. In energetic terms, you don't get something for nothing. Just doesn't happen (or not anywhere so far demonstrated, anyhow).

Gravity just cannot provide enough energy from falling sap (even if we overlook all the other flaws in your arguments, which are many). So how do you account for that? If you can't account for it then your theory has no scientific merit at all. And I will carry on thinking you a deluded fool, not just for wasting so much of your time and energy pushing your dead-end assertions about gravity, but also for your abject failure to look for the real causes of your apparently successful inclined bed ideas. If your results in that are really are as good as you claim it's not only yourself you're failing by apparently trying your best to discredit them with everyone who knows one end of an equation from the other.

In other news, if leaves can't support the "suction" of a column of water below them, how exactly are the (if anything more fragile) root systems of these great trees supposed to support the colossal pressure above them?

Journal of Experimental Botany, Vol. 48, No. 315, pp. 1753-1765, October 1997
Journal of
Experimental
Botany
REVIEW ARTICLE
The Cohesion-Tension theory of sap ascent: current
controversies
Melvin T. Tyree 1
USDA Forest Service, Aiken Forestry Sciences Laboratory, PO Box 968, S. Burlington, VT 05402, USA
Received 12 February 1997; Accepted 21 May 1997
jxb.oxfordjournals.org/cgi/reprint/48/10/1753.pdf

Gravity does not provide the energy?

Gravity is the energy, gravity drives the sun, the weather and all of life on earth! Perpetually for now at least!

Gravity can raise a mountain to impressive heights, cause tidal waves that demolish coastlines, cause volcanoes to erupt, yet cannot influence solutes inside a tree or indeed a human? Bullshit!