A tree stripped of a full ring of bark still lifts water to its leaves as usual, yet it slowly dies: the phloem sits on the outside and has been cut, so sugar can no longer reach the roots, while the inner xylem is untouched. The drier the air, the harder transpiration pulls, hauling the water column all the way to the treetop by cohesion-tension. At night that stream slows and root pressure pushes droplets out at the leaf margins, while inside the trunk lie the annual rings laid down by the cambium.
A tree stripped of a full ring of bark still lifts water to its leaves as usual, yet it slowly dies: the phloem sits on the outside and has been cut, so sugar can no longer reach the roots, while the inner xylem is untouched. The drier the air, the harder transpiration pulls, hauling the water column all the way to the treetop by cohesion-tension. At night that stream slows and root pressure pushes droplets out at the leaf margins, while inside the trunk lie the annual rings laid down by the cambium.
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