I dunno, maybe I missed the part of my education where I was supposed to learn how plants grow. Leaves do all the work, or 99% of the work, of using sunshine to build new molecules, so all the growing should be at the ends of the branches where the leaves are, right? But the big impressive part of the tree is the trunk, not the little branches and leaves. Now the tree gets water from its roots. The water gets piped up to the leaves because of capillary action and magic plant action (oxymoron, eh?), but how do our new molecules of plant get back down the branches to the trunk? Answer me that, Elmo.
New molecules of plant? The leaves let the water evaporate into the air and the sugar(food) is drawn back to the tree through the sapwood to feed the cambium layer when the leaves are done... unless it gets made into maple/birch/etc syrup.
ReplyDeleteYeah, the leaves are doing the work and when the tree is done with them they are trashed because they have no union.
Bark is the outer layer of a tree trunk - it provides protection. Next layer is phloem which is the layer which transports nutrients, sugars, etc. from the leaves to all parts of the tree. Cambium is next and consists of the living cells of the trunk - it makes new phloem and new sapwood (xylem) which is the next layer inward. Xylem can be thought of as being similar to long straws and draws water up the tree from the roots using capillary action. All these layers are just a fraction of the thickness of a mature tree but they’re where things happen to keep the tree growing. If you want to kill a tree just cut inward completely around the trunk and sever these layers. Such a cut is called girdling and it’ll kill the tree. B.S. Biological Sciences.
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