I’ve never understood how trees can exist.

This video looks plausible.

https://m.youtube.com/watch?v=BickMFHAZR0

mollwollfumble said:

I’ve never understood how trees can exist.

This video looks plausible.

https://m.youtube.com/watch?v=BickMFHAZR0

Interesting but he needs to calm down.

The Tree

The Rev Dodgson said:

The Tree

Bought that album back in the seventies.

Then there’s the trouble with the oaks and the maples

I’ve spent the last couple of days training some of the guys who are working on the intensive re-planting of Melbourne’s public spaces.

Trees are my friends.

Tree people are good people.

Bubblecar said:

mollwollfumble said:

I’ve never understood how trees can exist.

This video looks plausible.

https://m.youtube.com/watch?v=BickMFHAZR0

Interesting but he needs to calm down.

I’m calm with trees and existence.

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

Thank you. I was wondering why I was feeling nervous about accepting it.

mollwollfumble said:

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

Thank you. I was wondering why I was feeling nervous about accepting it.

https://academic.oup.com/treephys/article/37/1/18/2680809

roughbarked said:

mollwollfumble said:

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

Thank you. I was wondering why I was feeling nervous about accepting it.

https://academic.oup.com/treephys/article/37/1/18/2680809

https://academic.oup.com/treephys/article/33/3/238/1644569

roughbarked said:

roughbarked said:

mollwollfumble said:

Thank you. I was wondering why I was feeling nervous about accepting it.

https://academic.oup.com/treephys/article/37/1/18/2680809

https://academic.oup.com/treephys/article/33/3/238/1644569

www.clw.csiro.au/publications/waterforahealthycountry/2010/wfhc-Ord-trees-groundwater-interaction.pdf

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

1) I don’t see how using the other words would explain the mechanism any more clearly. I don’t see anything particularly buzzwordy about “negative pressure” anyway.

2) He said 2-5 nanometres. Maybe there’s new research. Maybe it varies. Maybe he just made it up. Don’t know.

3) He didn’t say it wasn’t. He was explaining how it can work over heights much greater than 10 metres, without requiring the alternative mechanisms that many people (including me) thought were required.

roughbarked said:

roughbarked said:

roughbarked said:

https://academic.oup.com/treephys/article/37/1/18/2680809

https://academic.oup.com/treephys/article/33/3/238/1644569

www.clw.csiro.au/publications/waterforahealthycountry/2010/wfhc-Ord-trees-groundwater-interaction.pdf

Thanks. Read those now.

I’m more interested in the relations between capillary curvature and pressure difference. How evaporation can occur across an adverse pressure difference. Experimental testing showing that water can maintain a negative pressure of -11 bar without boiling. And a paper on how a tree can survive after damage such as bushfire, insect attack, without all its sap boiling away.

https://en.m.wikipedia.org/wiki/List_of_superlative_trees

Tasmania does pretty well for tall trees. With 5 in the top 11.

mollwollfumble said:

https://en.m.wikipedia.org/wiki/List_of_superlative_trees

Tasmania does pretty well for tall trees. With 5 in the top 11.

Does well for amongst the oldest as well.

or should I say, did.

The Rev Dodgson said:

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

1) I don’t see how using the other words would explain the mechanism any more clearly. I don’t see anything particularly buzzwordy about “negative pressure” anyway.

2) He said 2-5 nanometres. Maybe there’s new research. Maybe it varies. Maybe he just made it up. Don’t know.

3) He didn’t say it wasn’t. He was explaining how it can work over heights much greater than 10 metres, without requiring the alternative mechanisms that many people (including me) thought were required.

Well I didn’t say it was shitty.

dv said:

The Rev Dodgson said:

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

1) I don’t see how using the other words would explain the mechanism any more clearly. I don’t see anything particularly buzzwordy about “negative pressure” anyway.

2) He said 2-5 nanometres. Maybe there’s new research. Maybe it varies. Maybe he just made it up. Don’t know.

3) He didn’t say it wasn’t. He was explaining how it can work over heights much greater than 10 metres, without requiring the alternative mechanisms that many people (including me) thought were required.

Well I didn’t say it was shitty.

OK, I suppose very nearly everything is suboptimal.

Young-Laplace equation.

dP=2*gamma/R
where gamma is the surface tension and R is the radius of curvature of the stomatal pores.

If for tallest trees, dP = 11 bar = 1.1 *10^6 N/m^2
gamma = 0.073 N/m

R = 2 * gamma / dP = 130 nanometres. So stomatal size has to be at most 0.26 µm.

That’s OK. But it is smaller than normal stomatal sizes. “Size varies across species, with end-to-end lengths ranging from 10 to 80 µm and width ranging from a few to 50 µm”.

It must be a hell of a job for those stomatal cells to accurately control the width to those tolerances under those conditions of pressure difference (1.1 MPa). That pressure will easily crumple sheet steel.

roughbarked said:

The Rev Dodgson said:

The Tree

Bought that album back in the seventies.

Then there’s the trouble with the oaks and the maples

Part of my early collection too (and still is).

The Rev Dodgson said:

roughbarked said:

The Rev Dodgson said:

The Tree

Bought that album back in the seventies.

Then there’s the trouble with the oaks and the maples

Part of my early collection too (and still is).

Yeah. I’ve still got it.

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

David Attenborough.. BBC Two
The Private Life of Plants Perfect pump, Growing

Ogmog said:

dv said:

This video is suboptimal.

1)
Negative pressure is a vague term and using such a buzzwordy phrase when there are proper grown-up expressions (tension, intermolecular forces such as hydrogen bonds) available helps no one.

2)
The elongated pathways (vessels) are from 50 nm up to a couple of microns wide, not a couple of nanometres.

3) Transpiration really is an important part of the process.

David Attenborough.. BBC Two
The Private Life of Plants Perfect pump, Growing

Thanks for the video. I hadn’t seen it before.

When one measures water pressure in trees, one will find it is highest in deciduous trees shortly before the leaves open in spring. At this time of year, water shoots up the trunk with such force that if you place a stethoscope against the tree, you can actually hear it.
There are no leaves = no transpiration.
Capilliary action can only be a partial contributor because the rise of three feet is hardly worth a mention.
Yet precisely at this time the trunk is full to bursting, leaving us with osmosis but this seems unlikely. As we know it, osmosis only works in the roots and leaves, not the trunk.

Scientists from three institutions. The university of Bern; the Swiss Federal Institute for Forest Snow and Landscape Research; and the Swiss Federal Institute of Technology in Zurich. Listened more closely – literally.

They registered a soft murmur in the trees, above all at night. At this time of day most of the water is stored in the trunk as the crown takes a break from photosynthesis and hardly transpires at all. The trees pump themselves so full of water that an increase in diameter has been recorded. The water is held immobile in the inner transportation tubes, nothing flows. So where are the noises coming from?
The researchers think that the noises are coming from tiny bubbls of CO2 in the narrow water filled tubes of the cambium. Bubbles in the pipes? This means that the supposedly continuous column of water is interrupted thousands of times.
If that is the case then cohesion transpiration and capilliary action contribute very little to water transport.

So many questions remain unanswered. Perhaps we are poorer for having lost an ecxplanation or richer in having gained a mystery?

copied in a slightly reworded format from: The Hidden Life of Trees ~ Peter Wohlleben ISBN 978-0-00-821843-0

roughbarked said:

When one measures water pressure in trees, one will find it is highest in deciduous trees shortly before the leaves open in spring. At this time of year, water shoots up the trunk with such force that if you place a stethoscope against the tree, you can actually hear it.
There are no leaves = no transpiration.
Capilliary action can only be a partial contributor because the rise of three feet is hardly worth a mention.
Yet precisely at this time the trunk is full to bursting, leaving us with osmosis but this seems unlikely. As we know it, osmosis only works in the roots and leaves, not the trunk.

Scientists from three institutions. The university of Bern; the Swiss Federal Institute for Forest Snow and Landscape Research; and the Swiss Federal Institute of Technology in Zurich. Listened more closely – literally.

They registered a soft murmur in the trees, above all at night. At this time of day most of the water is stored in the trunk as the crown takes a break from photosynthesis and hardly transpires at all. The trees pump themselves so full of water that an increase in diameter has been recorded. The water is held immobile in the inner transportation tubes, nothing flows. So where are the noises coming from?
The researchers think that the noises are coming from tiny bubbls of CO2 in the narrow water filled tubes of the cambium. Bubbles in the pipes? This means that the supposedly continuous column of water is interrupted thousands of times.
If that is the case then cohesion transpiration and capilliary action contribute very little to water transport.

So many questions remain unanswered. Perhaps we are poorer for having lost an ecxplanation or richer in having gained a mystery?

copied in a slightly reworded format from: The Hidden Life of Trees ~ Peter Wohlleben ISBN 978-0-00-821843-0

I’ve read that book, but didn’t recall the bit about CO2 bubbles.

I think there is more to be revealed.

The Rev Dodgson said:

roughbarked said:

When one measures water pressure in trees, one will find it is highest in deciduous trees shortly before the leaves open in spring. At this time of year, water shoots up the trunk with such force that if you place a stethoscope against the tree, you can actually hear it.
There are no leaves = no transpiration.
Capilliary action can only be a partial contributor because the rise of three feet is hardly worth a mention.
Yet precisely at this time the trunk is full to bursting, leaving us with osmosis but this seems unlikely. As we know it, osmosis only works in the roots and leaves, not the trunk.

Scientists from three institutions. The university of Bern; the Swiss Federal Institute for Forest Snow and Landscape Research; and the Swiss Federal Institute of Technology in Zurich. Listened more closely – literally.

They registered a soft murmur in the trees, above all at night. At this time of day most of the water is stored in the trunk as the crown takes a break from photosynthesis and hardly transpires at all. The trees pump themselves so full of water that an increase in diameter has been recorded. The water is held immobile in the inner transportation tubes, nothing flows. So where are the noises coming from?
The researchers think that the noises are coming from tiny bubbls of CO2 in the narrow water filled tubes of the cambium. Bubbles in the pipes? This means that the supposedly continuous column of water is interrupted thousands of times.
If that is the case then cohesion transpiration and capilliary action contribute very little to water transport.

So many questions remain unanswered. Perhaps we are poorer for having lost an ecxplanation or richer in having gained a mystery?

copied in a slightly reworded format from: The Hidden Life of Trees ~ Peter Wohlleben ISBN 978-0-00-821843-0

I’ve read that book, but didn’t recall the bit about CO2 bubbles.

I think there is more to be revealed.

I daresay.

roughbarked said:

The Rev Dodgson said:

roughbarked said:

When one measures water pressure in trees, one will find it is highest in deciduous trees shortly before the leaves open in spring. At this time of year, water shoots up the trunk with such force that if you place a stethoscope against the tree, you can actually hear it.
There are no leaves = no transpiration.
Capilliary action can only be a partial contributor because the rise of three feet is hardly worth a mention.
Yet precisely at this time the trunk is full to bursting, leaving us with osmosis but this seems unlikely. As we know it, osmosis only works in the roots and leaves, not the trunk.

Scientists from three institutions. The university of Bern; the Swiss Federal Institute for Forest Snow and Landscape Research; and the Swiss Federal Institute of Technology in Zurich. Listened more closely – literally.

They registered a soft murmur in the trees, above all at night. At this time of day most of the water is stored in the trunk as the crown takes a break from photosynthesis and hardly transpires at all. The trees pump themselves so full of water that an increase in diameter has been recorded. The water is held immobile in the inner transportation tubes, nothing flows. So where are the noises coming from?
The researchers think that the noises are coming from tiny bubbls of CO2 in the narrow water filled tubes of the cambium. Bubbles in the pipes? This means that the supposedly continuous column of water is interrupted thousands of times.
If that is the case then cohesion transpiration and capilliary action contribute very little to water transport.

So many questions remain unanswered. Perhaps we are poorer for having lost an ecxplanation or richer in having gained a mystery?

copied in a slightly reworded format from: The Hidden Life of Trees ~ Peter Wohlleben ISBN 978-0-00-821843-0

I’ve read that book, but didn’t recall the bit about CO2 bubbles.

I think there is more to be revealed.

I daresay.

I speculated is a cartoon that trees have hundreds of millions of tiny pumps.

I don’t believe it, but the observation of sound is not inconsistent with the hypothesis.

mollwollfumble said:

roughbarked said:

The Rev Dodgson said:

I’ve read that book, but didn’t recall the bit about CO2 bubbles.

I think there is more to be revealed.

I daresay.

I speculated is a cartoon that trees have hundreds of millions of tiny pumps.

I don’t believe it, but the observation of sound is not inconsistent with the hypothesis.

Why don’t you believe it?

They must have pumps of some sort, and they must be very small.

The Rev Dodgson said:

roughbarked said:

When one measures water pressure in trees, one will find it is highest in deciduous trees shortly before the leaves open in spring. At this time of year, water shoots up the trunk with such force that if you place a stethoscope against the tree, you can actually hear it.
There are no leaves = no transpiration.
Capilliary action can only be a partial contributor because the rise of three feet is hardly worth a mention.
Yet precisely at this time the trunk is full to bursting, leaving us with osmosis but this seems unlikely. As we know it, osmosis only works in the roots and leaves, not the trunk.

Scientists from three institutions. The university of Bern; the Swiss Federal Institute for Forest Snow and Landscape Research; and the Swiss Federal Institute of Technology in Zurich. Listened more closely – literally.

They registered a soft murmur in the trees, above all at night. At this time of day most of the water is stored in the trunk as the crown takes a break from photosynthesis and hardly transpires at all. The trees pump themselves so full of water that an increase in diameter has been recorded. The water is held immobile in the inner transportation tubes, nothing flows. So where are the noises coming from?
The researchers think that the noises are coming from tiny bubbls of CO2 in the narrow water filled tubes of the cambium. Bubbles in the pipes? This means that the supposedly continuous column of water is interrupted thousands of times.
If that is the case then cohesion transpiration and capilliary action contribute very little to water transport.

So many questions remain unanswered. Perhaps we are poorer for having lost an ecxplanation or richer in having gained a mystery?

copied in a slightly reworded format from: The Hidden Life of Trees ~ Peter Wohlleben ISBN 978-0-00-821843-0

I’ve read that book, but didn’t recall the bit about CO2 bubbles.

I think there is more to be revealed.

In this report: published here https://www.abc.net.au/news/science/2019-07-26/living-stump-discovered-in-new-zealands-kauri-forest/11341608
“Their study, published on Friday in the journal iScience, provides the first evidence neighbouring trees directly share water through their root systems.

“Water transport between a living stump and a tree has never been shown in any species,” Dr Leuzinger said.

“If these results can be confirmed, we’ll have to completely revise our view of how forests work.”

In the above mentioned book, the author describes having come across what he at first thought were mossy stones until his curiosity caused him to look more closely and discover that they were tree stumps which had been felled five hundred years before yet were still alive. Just stumps with living bark.