How do Trees Really Lift Water To Their Leaves?

So wrong and so far off the mark about where this is heading Sophie. I do learn from you and others, my lesson might not go in the direction you anticipate but that is the problem with people who think laterally rather than a blinkered approach.

I have taken on board all of the posts and let's face it they are available for reflection and are being read by the doctor who has agreed to help with the paper. The real shame is that the significance of all of this appears to go over your heads.

You said science does not suck in that it can be explained better by pressure changes. The cohesion tension theory has an elaborate explanation stating that as one water molecule leaves the tree to the atmosphere another is drawn up to replace it. Well blow me if this was the case we would have water spurting out of the tops of buildings filled with cavity wall insulation and all of the water would leave the top of the tree rather than the observed source to sink flow.

Picture a deciduous tree in Autumn with all of it's leaves on the ground standing 40-50 metres as naked as a newborn. The cohesion tension theory states evaporation from the leaves causes water to be sucked up, SUCKED being the appropriate term for one molecule replacing another in a vertical chain from root to leaf. Well blow me again there are no leaves to suck here yet the buds begin to burst in the upper most branches during the spring. How does your precious historic science deal with this obvious anti-suck observation? It can’t can it? Only a density change be it from the warming of the outside of the tree or from the release of stored salts and sugars or even a combination of both can explain this new burst of life in what is after all a multiple conduit system consisting of predominantly non living tubular cells.

Another argument is that the collective pull of the densely leaved canopy can account for the impressive heights of trees. Well blow me again there are many trees locally that have very little canopy yet continue to grow vertically and have done so for some 21 years. Larch being a prime example.

The problem science is having at the moment is accepting that trees do not suck water up and emit it to the atmosphere, they circulate sap and some of it is emitted to the atmosphere and as a result of the water loss inevitable density changes take place!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
http://www.thenakedscientists.com/forum/index.php?topic=1982.msg263170#msg263170