Botanic problem 3

Exhibit 3.

Passing exhibit 1 (see almost immediately below) on the Horton Clockwise on a regular basis, I have often wondered how the pipe work works at junctions. A wonder which was sharpened during the winter storms by exhibit 2 (see immediately below), showing a junction which has ripped apart.

All of which moves me today to prepare exhibit 3.

Diagram IV is a tree in the ground. We suppose for simplicity that water and other stuff from the ground enters by the roots, travels up through the tree, into the branches and out through the leaves.

Diagram I shows a portion of trunk, with the vertical lines being the water pipes. I remember their being arranged around the outside of the trunk, more or less immediately under the bark, from O-level biology (after the examinations for which I remember collecting a small prize); roughly speaking the interior takes the weight while the exterior takes the traffic. The evidence for this includes the dampness of the newly exposed meat of a young trunk when you strip the skin off. We suppose that the water pipes are so organised that they can only carry water up and we leave aside the other set of pipes which brings some of the products of photosynthesis down. We further suppose that pipes cannot branch as that only pushes our problem down a level.

But trees do have a branching instinct, my first stab at which is diagram II, it being rather as if one had stuck one's thumb into the casing of the tree from the inside, pushing a growth out, taking the nearby pipes with it. Which leads is to diagram III, which has not only generated an awkward singularity at A, but also has pipes which are useless, running down the let hand side of the new branch and then on up the right side of the old trunk, pipes which are not connected to anything useful. So evolution discarded that line of development.

A second line of attack is shown at diagram V, where at the right we have new loops of pipe growing from the base. These push out into the growth at diagram VI and on into the completed branch at VII, this time with the awkward singularity pushed up a bit to B. But at least the pipes work in this arrangement. But not all that well or we would not getting the odd scarring in exhibit 1 and the breach at exhibit 2.

One day I will find a botanist who will be able explain what actually goes on. My bet is that whatever wheeze one comes up with there is going to be a singularity in the AB region, a singularity which is a weakness.